At the beginning of the film, you see Robert Carlyle passing under a partially constructed bridge about a hundred yards from Tower Bridge, yet when the Tidal Surge is heading up the Thames and nearing Tower Bridge, this partially constructed bridge is nowhere to be seen.
The fighter bomber shown on the ground was a single seater, however, the plane shown taken off is a Tornado GR4, which is a two seater.
In flight scenes involving the Tornado GR4 it is plainly only carrying 2 fuel drop tanks and nothing else. If was sent to destroy the Thames Barrier it should be carrying air-to-ground missiles.
When Rob Morrison is looking for a life raft below water near the boat, he damages his leg and there's a lot of blood showing in the water. Later when they escape to the underground, his leg seems to have repaired itself. He walks with apparent ease, no pain, and no blood.
After Sam gives the order to initiate Barrier closure, we see a distance shot showing the gates completely closed. When the surge is rushing up towards the gates, however, a distance shot shows the gates completely down. The gates are then shown closed again during the close-up shot of the surge overtopping them.
Although the senior military advisor is referred to frequently as 'Major General' his rank badges are those of a (full) General. In addition, a Major General would be normally be addressed as 'General'.
The helicopter taking the Deputy Prime Minister to Scotland bears a ZS- Registration for South Africa, not a G- Registration as would be expected. Furthermore he would have been flown by the Military in such an instance.
The Thames Barrier is shown closing all gates in around 30 seconds. In fact, it is closed progressively over two hours. Any more suddenly would cause a damaging reflective wave to "bounce" off the gates.
At the beginning of the film the wave heights are report in feet. The UK Meteorological Office, as does all meteorological and marine agencies, record wave heights and tidal ranges in meters.
In one scene, its very obvious that the Prime Minister's helicopter is a fake, toy one.
While Sam is setting the high tide closure status to Amber, Frank turns and can be seen talking to a couple men in the background. However, the faint audio one can hear of him right then is clearly the exactly same words he says to Rob later in the film: "Our in-house guys inspect year-round..."
The emergency team is referred to as COBRA. Technically, this refers to the location, Cabinet Office Briefing Room A, the actual group of people coordinating the emergency effort is the Civil Contingencies Committee or "Triple-C".
At one point in the film, the authorities are alerted that St. Thomas' Hospital could not be evacuated in time; at this point the map correctly shows the hospital as located in Lambeth, right on the east bank of the Thames. Earlier in the film, however, a map shows the hospital located in Borough, right on the south bank; online maps show a Starbucks in that location instead.
Wick is shown in the opening scene as being in the Western Isles. A later news report appears to show it on Scotland's east coast south of Aberdeen. In fact it is on the east coast north of Aberdeen.
When the film shows Embankment station, it is actually Charing Cross Underground.
Just before the news helicopter reports that there are survivors stranded on rooftops, a scene shows the helicopter from below. The tall brown building in the far right of this shot of the helicopter is Safmarine House, which is situated in the Cape Town CBD.
There's a lot of discussion and some scenes dealing with school evacuation. However, given that the authorities' first real awareness of the danger doesn't happen till after 4 p.m., and the water doesn't hit the mouth of the estuary till after 7 p.m., the schools should be out of session for the day, and no evacuation of schools should be necessary.
Surprisingly the panicking Londoners tried to leave London rather than take the simplest and most obvious way to escape from the floodwater - seek refuge on the top of buildings. Warnings to seek high ground (which could be said to imply rooftops and such) can be heard when the evacuation alert is first issued, but they seemed to have been ignored or forgotten by evacuation personnel later, and certainly by the crowds shown.