...affects flights from Ghana
Air travel to and from Britain has been plunged into chaos in the wake of the discovery of a plot to blow up airlines on transatlantic flights.

Many airlines said they were cancelling all flights to Britain and to the epicentre of the threat, London Heathrow, one of the world's busiest airports. Heathrow was closed this morning to incoming flights in the wake of today's anti-terror operation. Flights to/from Ghana are expected to be affected

Airport operator BAA asked that all flights still on the ground should not take off for the airport.

But National Air Traffic Services (Nats), which runs air traffic control, said flights already heading for Britain's biggest airport would be allowed to land.

A Nats spokesman said: "BAA has asked that no flights due to come to Heathrow be dispatched."

He added that some flights were able to leave Heathrow and were being handled by Nats in the normal way.

The move came as several airlines suspended services to the UK because of the major disruption caused by tightened security measures.

Charlotte Demant, a make-up artist, has been in Ghana for two weeks and was on her way home to Denmark.
She said: "I can understand why they are worried about security but the airline has not been helpful.
"We should have at least been given something to eat and drink and money to phone home. I'm going to end up spending the night here in the cold airport."

UK threat level 'Critical'

HOME Secretary John Reid today said the terrorist threat to the UK had been raised to "Critical".
Speaking at a press conference following the foiling of the airport bomb plot, he said: "Overnight the police, with the full knowledge of Ministers, have carried out a major counter-terrorism operation to disrupt what we believe to be a major threat to the UK and international partners.
"At 2am this morning the Joint Terrorism Analysis Centre raised the UK threat state to its highest level - critical.
"This is now being publicly announced as I promised to Parliament last month.
"This is a precautionary measure. We are doing everything possible to disrupt any further terrorist activity.
"This will mean major disruption at all UK airports from today.
"But as far as is possible we want people to go about their business as normal.
"The police will provide an update on the operation later this morning and Ministers will keep the public regularly informed."
The UK has five security threat levels which are designed to give a broad indication of the likelihood of a terrorist attack.
They are low - an attack is unlikely; moderate - an attack is possible, but not likely; substantial - an attack is a strong possibility; severe - an attack is highly likely; critical - an attack is expected imminently.
Threat levels are set by the Joint Terrorism Analysis Centre (JTAC), a group of police and security service counter-terror officials set up in 2003.
JTAC bases its decisions on a range of factors including intelligence, recent events and what is known about terrorist intentions and capabilities.
The raising of the threat level from Severe to Critical today automatically triggered, as passengers at airports found out this morning, maximum protective security measures.
Such a move would be a response to intelligence about specific, imminent threats, according to MI5’s website.
But MI5 admits that security intelligence gathering is an imprecise science - the national threat level was famously lowered from Severe to Substantial just before last year's July 7 suicide bombings in London.
The security service's website states: "It is rare that specific threat information is available and can be relied upon. Intelligence is only ever likely to reveal part of the picture."