Continuity mistake: When Bridget's boss at the TV show tells her he wants her to cover the Kafir/Heeney case (the freedom fighter), Bridget is playing with her pen over her right shoulder. The shot then shows her boss is talking to her, but neither her hand nor pen are up - in the next angle of her, she is still waving her pen up by her right shoulder.
Audio problem: When the men are fighting in the street, Bridget and her friends are talking about who to root for, and Bridget's mouth doesn't match what she is saying at all.
Continuity mistake: When Bridget is at the "tarts and vicars" party, her "uncle" Geoffrey pinches her bunny tail for the second time - when he bends over to pinch it he has a straw (or maybe a cigarette?) in his mouth. Just as he does this, Bridget's mother comes along and slaps his hand, he pulls up and there is nothing in his mouth.
Deliberate mistake: When Mark is catching a cab outside "JFK" airport, the cars are driving on the left hand side of the road - if they were in America they would be going the wrong way (the director points out in the commentary that this shot was filmed in London to save money).
Continuity mistake: When Bridget is writing in her diary about the kind of man she must not go for, she is writing on the left page. When the voice over says "And especially must not fantasize about particular person who embodies all these things" there is a close up and she's writing on the right page. Seeing as her diary has a page per entry, not really probable that this would happen.
Other mistake: The last name in the credits from the cast is called Melinda, when in actual fact, the character in the film is called Melanie.
Factual error: After Bridget arrives back in London from a visit to her parents, the camera pans away to reveal the train on which she is supposed to have travelled. You can tell from its distinctive yellow and white exterior that it's a Connex train, but these only run on the suburban commuter routes through south London to East Sussex, Surrey and Kent - nowhere near Mr and Mrs Jones's Cotswold home. Rail services from the Cotswolds are operated by First Great Western (grey high speed trains) and Thames Trains (navy blue exteriors) and terminate at Paddington in west London.
Continuity mistake: When Bridget, Daniel and the other guy are in the lift at the start, Bridget is in the centre of the lift. The other guy gets out and Mr. Fitzherbert replaces him. Then Daniel gropes Bridgets bum and we see them all get out - Bridget is suddenly in the corner, but the whole time she never moved. (00:15:00)
Other mistake: When the two gents are fighting in the restaurant Hugh Grant tackles the guy through the plate glass window and they land on the street. Two points: 1) How do they not receive any cuts from landing on shattered plate glass. 2) Check out the glass laying on the street. It is cloudy, a main characteristic of breakaway stunt glass.
Continuity mistake: After Bridget sprays the contents of the blender all over herself, there's a splodge on her right cheek - it changes shape when she answers the door. (01:01:10 - 01:02:00)
Continuity mistake: At the Darcy's party, near the end of the movie, Bridget's hair changes constantly: smooth to slightly mussed, barrette visible then covered with hair, and the location of her part shifting a bit.
Factual error: One that only Londoners would notice or care about, but anyway: Bridget's flat is supposed to be in the trendy bit of Southwark, near Borough Market, i.e. south of the river. Right at the end, when she pursues Mark Darcy, the shop where she catches up with him is clearly in the City of London (the very distinctive Corporation of London bollards are all around, and the shop itself is on Threadneedle St, I think) - meaning that he's walked and she's run right across Southwark Bridge and up King William St in about thirty seconds...
Other mistake: When Bridget's friends come over to her home they always need to call up first. She then can buzz them in by pressing a button that unlocks the building's main door. Yet when Bridget first runs from her flat after Mark with just her bare feet you can hear her feet crunching on snow. She then runs back inside to put on her shoes and a sweater. If she really needed to buzz her friends in then there should have been a hallway where she ran first and not the outside directly. [As an addition: when Mark comes to Bridget's door to show her the newspaper article, as he says ...'I may have come at a bad time...' you can see a hallway behind him. When she runs outside at the end of the movie there is, for some reason, a different set outside her doorway. For example, when Bridget opens the door to run after Mark, it looks like she is running into bright sunlight - lighting way too bright for hallway illumination and especially out of sync with the evening sky.]
Factual error: When Darcy leaves England and goes to New York City. He steps out of the terminal and a big banner reads Welcome to New York. Then he stops by a speed limit sign that said 15 miles per hour. Problem....that sign is red with white letters. The U.S. speed limit signs are not that color. Therefore, that airport was NOT in New York and they were saving money on production. I guess the banner helped.
Other mistake: When Bridget and Mark kiss at the end, he puts his coat round her. The coat is huge! It's obviously specially made because before it wasn't as big as that.
Continuity mistake: There are two types of string used in the blue soup scene - plasticky type that florists sometimes use for the blue stuff, then ordinary string for when the dye has come out.
Continuity mistake: While Bridget and Daniel are driving to their "full-blown mini-break holiday weekend", Bridget lifts the sunglasses over her forehead with her left hand and holds the scarf at her neck with her right hand, but in the next shot before her scarf blows off her hands are in the opposite positions. (00:31:10)