Factual error: The contract Stone and his team force Carlton Wood and Harry Fielding to sign guaranteeing Fowler's widow the royalties from his invention for life is signed under duress and is therefore invalid. It is hard to believe that none of Stone's team don't know this, but it is impossible to believe that Carlton Wood wouldn't.
Factual error: Mickey and Danny walk to their local shop to buy ice. We see that the shop is Robis, which is at 106 Brick Lane, in E1. They even show the street name sign just so we can be certain. Mickey and Danny deliver the ice to their flat, which is in the street directly opposite the shop - the camera shows them going into the building. However, a few shots later, the whole crew meet on the roof of the building to discuss The Henderson Challenge. We see that this building overlooks the north side of the river, close to Tower Bridge. We get a clear view of the Greater London Authority building which is on the opposite, south bank. They are suddenly several kilometers from Brick Lane, which is where their flat was just shown as being.
Factual error: They plant Albert's hair on a brush used by the Queen Mother in order to have a DNA sample taken from it match that taken from a hair plucked out of his head by Francis Owen, their mark. The Queen Mother's (non-existent) son would not have the same DNA as her. It could be used to establish a biological relationship but it would not be identical - it could not be. First, Albert's DNA is identifiable as that of a male. The lab testing the sample supposed to be the Queen Mother's would see that immediately. Second, a son's DNA is not identical to either of his parents or his siblings (if any) - it is at least 50% different. Any lab worth their fee would realise in a second that the two samples were from the same person. Another problem - Owen plucks the hair from Albert's head and Stacie handles the hair from Albert she plants on the hairbrush with bare fingers, in both cases hopelessly contaminating the samples with their DNA. The tests really are that sensitive.
Factual error: The laboratory technician uses a bog standard light microscope to match the two DNA samples, one from Albert and one allegedly from the Queen Mother. That's absurd. DNA samples are compared using a procedure known as SDS-PAGE, otherwise known as gel electrophoresis. This produces the familiar chart we know as DNA "fingerprints" - bands of light and dark showing the composition of a DNA sample which has been broken up by enzymes. You cannot examine DNA with a light microscope - you couldn't even do it with a scanning electron microscope.
Plot hole: Mickey Bricks returns to England by stealing the uniform of a Commander Cardwell, an officer in the Royal Navy, and taking his place on board an aircraft carrier that is sailing from Australia to the UK, leaving that day, a voyage that would take three to four weeks. During that time, Cardwell does not report his uniform stolen, nor does he report to the aircraft carrier to take up his duties, and since there was a car waiting to take him to the ship he is obviously supposed to be there. Theft of a military uniform is taken extremely seriously and once reported it would take no time at all to establish that "Cardwell" appears to be on board his ship! On top of that, during his entire time at sea nobody on board calls upon Mickey to perform any sort of military duties (of which he would have absolutely no knowledge), he doesn't run into anyone who knows Cardwell, and nobody asks to see his orders, military identification or travel warrant.
Plot hole: The gang plan to sell 100 kilograms of gold to their mark Dexter Gold for £500,000. In fact they show him 100 standard gold ingots, not 100 smaller 1 kilogram ingots which are about the size of a small mobile phone. A standard gold ingot weighs 12.4 kilograms. They are showing him 12,400 kilograms of gold - nearly 12 ½ tonnes! First, Gold is an expert. He would know right away that they couldn't possibly be offering 12 ½ tonnes of gold for half a million pounds. Nobody is that stupid - that amount of gold would be worth two hundred and fifty million pounds! Secondly, he would be aware of the difference between a standard 12.4 kg and a one kg ingot. Thirdly, they have the fake gold stacked on an ordinary wooden pallet. That amount of gold (or anything else) would crush it like tissue paper - and it could not possibly be transported in an ordinary Army truck like the one shown.
Factual error: Ash tells the gang that corrupt politician Rhona Christie "took a marginal seat", which we know includes the youth club in Poplar, Greater London. In fact Poplar and Limehouse is an ultra safe Labour constituency. The sitting member has a majority of over 20,000. It has never been even close to marginal, and a meticulous researcher like Three Socks Morgan wouldn't make a mistake like that.
Factual error: Albert and Emma pose for phony wedding photographs in front of a green chromakey screen in order to have a new background created on computer. However, Emma is holding a garland of flowers surrounded by green foliage. You can't have anything green in the foreground when using green chromakey as it will drop out too and become part of the superimposed background.
Plot hole: At the end of the episode, having conned Veronica Powell out of £600,000 - the purchase price of the house and contents they sold her - Danny taunts her by telling her that they did nothing wrong, implying that she has no legal recourse to recovering her money. He's wrong. One of the gang, Billy Bond, bids against her in the auction for the house, boosting her bid from £220,000 to her final offer of £600,000. Bond has no money and no access to any, and no assets that could be realised to cover the bids he made, something that would be easy for a lawyer to prove. It's called shill bidding and it is very illegal indeed. Since Bond and Ash Morgan (who gave Powell false information during the auction, spurring her on to bid against Bond) are both standing next to Danny when he makes his announcement I find it hard to believe that a shrewd, hard-hearted businesswoman like her would not realise that she had been conned and would not get her lawyers and the police on the case on the spot.
Character mistake: Albert tells Ash that during his service in the UK with the U.S. Air Force he was required to join a squad flying back to the United States in a "B29 Fortress." The B29 Superfortress was not used in the European theatre during World War 2 - it was used exclusively in the war against Japan in the Pacific. The B17 Flying Fortress was a different aircraft. Anybody in the US Air Force at the time would know the difference, and it is not a mistake a veteran would make.
Other mistake: In a number of episodes Mickey Bricks takes great pains to explain (usually to bent coppers) that he and his team are not thieves, making it plain that as a talented grifter he takes the high moral high ground over common criminals. The trouble is, he and every member of his team ARE thieves. In the very first episode "The Con Is On" Three Socks Morgan cleans out the bank accounts of a number of innocent people by rigging an automatic teller machine. He is stealing money, either from them or the bank. Stacie Monroe is shown picking pockets in a number of episodes and in "The Henderson Challenge" both Mickey and Danny Blue steal wallets from bystanders, a trick Mickey repeats in "The Return of the Prodigal." He also steals the victim's car. There are too many other examples to list here, but Mickey's pride in his exalted position as a master conman is definitely misplaced.
Character mistake: The plan hatched by Carlton Wood and Harry Fielding makes no sense at all. They recruit three people who they think were victims of Micky Bricks' crew, asking them each to deposit a cheque for £1,000,000 into an account that their accomplice Alfie will show to Albert Stroller to "prove" his wealth. They are on a hiding to nothing. A bank statement will always show a ledger balance - all funds including uncleared cheques - and an available balance, the amount of money in the account that can be withdrawn at any one time. Alfie's account will show an available balance of nil and will convince nobody of anything. A city wideboy like Wood would know this and would ask for the deposits to be made by account transfer or even in cash, or he could even cut out of the middle men and prepare a fake bank statement. A ruthless businessman like him would have no trouble at all arranging a simple thing like that. The way he does things is uncharacteristically clumsy and includes nothing but loose ends.
Plot hole: The only people who respond to Harry Fielding's classified ad seeking victims of the gang are three people who, it turns out, are actually working with Mickey Bricks. Considering how prolific the grifters are I rather think Fielding would be inundated with genuine people seeking revenge, but not one shows up. Not one? Simply unbelievable.
Plot hole: At the end of the episode Trevor Speed sits with his face in his hands looking like the world has stopped turning. In fact he has just sold a worthless plot of land for £450,000. Okay, he was conned out of £150,000 of that by the grifters, but he is still £300,000 up. A grifter like him would be over the moon - he is used to taking elderly ladies for the occasional short con making him £80 or so. He's just won the lottery. He'd be happy.
Character mistake: Near the end of the episode Danny refers to the money they have stolen, saying "Stacie is sitting next to half a million big ones." Anyone familiar with grifter slang knows a "big one" is a thousand dollars (or pounds, etc.) - certainly Danny Blue would know that. He just said that they have half a billion dollars in their hands. Not a mistake Danny Blue would make.
Plot hole: At the end of the episode Stacie says that she has cashed the bank draft used to purchase the forged comic book artwork. Not a chance. The auctioneers establish that the artwork is a forgery within minutes of the sale going through and they would be onto their bank immediately ensuring a stop order was put on the draft. Bank cheques and drafts can be stopped after issue - it happens all time. In fact, simply by presenting the draft Stacie has opened herself up to a world of legal problems - the bank's computers are going to light up like a Christmas tree and the police will be there within minutes.
Plot hole: During their assessment of the security in operation at the Syrian bank they intend to rob, Mickey and his team discuss in some detail the regular patrols of the safety deposit box vaults by guards leading attack dogs. These guards are conveniently forgotten about during the heist, even though there has been a power failure knocking out all but one of their electronic safeguards. You'd think there would be increased and more thorough patrols by the guards at that time - instead they just disappear.