Despite repeated requests, Malaysia's Department of Civil Aviation is refusing to publish a report into the allegations. Britain's Department of Transport has the report, but does not believe it should publish it.
The low-fuel allegations were first reported by an anonymous Heathrow worker. Suspicions were raised when a 747 pilot demanded to go to a stand nearer the runway than the one originally allocated.
The servicing team from British Airways found that the 747 landed with just 3.4 tons of fuel. British aviation rules require at least five tons and British Airways requires nine tons in its aircraft. Had the aircraft been unable to land at Heathrow it did not even have enough fuel to make it to Gatwick. The whistleblower's report said the same airline had been involved in 10 similar incidents at Heathrow.
According to sources close to Malaysian Airlines, the problems are associated with the company's fuel policy, which puts pressure on pilots to carry the minimum acceptable levels of fuel. Extra fuel increases the aircraft's weight and therefore operational costs. Malaysian Airlines has 14 flights a week between Kuala Lumpur and Heathrow. Depending on various factors, including weather, the aircraft should start with at least 160 tons of fuel on board for the 14-hour flight.
Malaysian Airlines has denied the allegations. But after a meeting with Department of Transport staff, the then-minister, Glenda Jackson, said: "Malaysian Airlines has co-operated fully with the department in reviewing its fuel policy and examining why, on a very few occasions, low levels may have been recorded at the completion of a flight."
Malaysian Airlines has also agreed to provide the British Government with weekly reports of fuel levels on all its aircraft on arrival in Britain.
Ms Jackson ordered the Civil Aviation Authority to toughen up its spot-check regime on fuel levels in foreign jets. Under international air safety rules, complaints are investigated by the carrier's national civil aviation authority.