Alarming security breaches and health and safety gaffes at Heathrow have been revealed in an investigation of dangerous incidents at UK airports.

Among the incidents was a container of undeclared bacterial stock that toppled over and leaked high pressure gas in the hold of an aircraft last January.

On another occasion, a group of passengers with tickets to Singapore boarded a wrong flight to India. Only when the correct passenger saw his seat taken was the mistake identified Five UK airports - Glasgow, Belfast International, Manchester, Birmingham and London Heathrow - reported more than 1,100 potentially dangerous safety and security incidents in 2007.

The BBC obtained figures under the Freedom of Information Act.

Among one of the most serious incidents, strong oil fumes caused an air crew at Heathrow to experienced throat irritation and light headedness while pilots on a separate flight had to put on oxygen masks because of the same problem.

A pilot bringing a packed lunch into the cockpit caused the most unlikely safety risk after a small round object rolled out from under the pedals which had been causing "restriction to the rudder control" - it turned out to be a plum.

There are no publicly available figures for safety and security incidents at major UK airports for previous years.

But a Civil Aviation Authority spokesman told the BBC that the 2007 figures did not indicate that passenger’s safety was being put at regularly risk.

He said: "Over two million commercial flights operate in UK airspace every year, while Heathrow handled over 477,000 flights.

"It must be noted that the occurrence reports filed will vary greatly in their severity, and therefore conclusions cannot be drawn from a simple assessment of the number of occurrences for a set subject."