A woman who was denied entry to a packed British Airways flight from Paris to London on Sunday sparked a full-blown security alert after saying the plane was going to explode.

The unidentified would-be passenger, who is in her 50s, was arrested after making the threat at Charles de Gaulle airport, the busiest in France.

It led to the Airbus A320 having to be evacuated and then grounded, as police and emergency services vehicles surrounded it.

The had woman got to the airport before flight BA0303 was due to set off from Terminal 2A at 7.25am, but she was not allowed to board because she did not have a valid ticket.

Passengers were ordered off the British Airways Airbus A320 shortly before it was due to depart Paris Charles de Gaulle for London Heathrow Airport this morning

Armed police individually searched all the passengers while sniffer dogs checked the aircraft

Passenger James Anderson said 'a direct threat' had been made against the aircraft

According to an investigating source speaking to AFP, she was 'taken into custody on suspicion of claiming that the Heathrow-bound plane, with 130 passengers on board, was going to explode'.

All those involved had to be screened again, and their luggage was also re-inspected by security officials.

Pictures on social media show passengers being evacuated from flight BA303.

Sniffer dogs went on board the Airbus along with their handlers, and it was not until 11.10am that the flight finally left. It landed safely at Heathrow Terminal Four 45 minutes later at 11.55am.

Passenger James Anderson wrote on Twitter: 'On British Airways flight BA0303, currently being held on tarmac at Paris due to security threat, surrounded by police and fire vehicles.

'Apparently an individual has made a direct threat to this aircraft. We will all be led off the aircraft and baggage searched in due course.'

Mr Anderson claimed 'Everybody's been individually searched by armed officers and given the all clear. Now hold luggage being searched by dogs.

'Initially the pilot told us there were technical issues. We were waiting on the plane for around an hour. We were then told the aircraft had to move to another part of the airport.

Passengers on board a British Airways flight between Paris Charles de Gaulle and London Heathrow have been evacuated after a 'direct threat' was made against the Airbus A320

'That's when we noticed police and fire vehicles quickly surrounded the plane and dozens of armed officers and firefighters got out. The pilot then said there had been a direct security threat involving our flight specifically.'

Then Mr Anderson Tweeted: 'Aircraft has been deemed absolutely safe. Authorities are satisfied with the search. We will continue on to London Heathrow.

'Our pilot was an absolute credit to British Airways. Extremely calm and composed, handled the situation wonderfully.'

A British Airways spokesman said: 'The safety and security of our customers and crew is always our top priority.

'Additional security checks are being carried out as a precaution. We would never operate a flight unless it is safe to do so.'

After the aircraft's departure, British Airways added: 'Following additional security checks this morning, the flight has now taken off.'

France remains under a State of Emergency following a series of terrorist attacks carried out by ISIS and al-Qaeda operatives.

This means that security checks are carried out regularly at transport hubs such as airports, and train stations, often without warning.