Ministers have offered to help in the financial crisis in air traffic control, which staff say is compromising safety.

Controllers' union Prospect had called for "immediate government intervention" to address the lack of money and staff at the part-privatised National Air Traffic Services (Nats).

In a letter to Transport Secretary Alistair Darling, revealed on Sunday, staff warned that the cash crisis would mean further delays and safety risks.

In response, the transport department said it recognised there were problems and would work towards a solution.

Last year was the safest year on record

Nats spokesman

A statement said: "We recognise that Nats finances do need strengthening.

"All parties with an interest in that are working together towards a long-term solution that will put Nats finances on a sound footing.

"The government is prepared on the right terms to match investment in Nats by a third party."

The statement added that earlier this year the government and banks had each made �30m available "to ensure Nats' short-term liquidity".

'Penny-pinching'

A letter obtained by the Independent on Sunday newspaper revealed the fears among staff.

Prospect's national secretary, David Luxton, writes: "The combination of financial pressures and operational overload will lead to air traffic safety being compromised and service levels degraded."

But a Nats spokesman defended its safety record and said: "Last year was the safest year on record."

"The figures for the first seven months of this year, which are still to be assessed independently, show that the safety performance is better than the same period last year."

Staff at the new Swanick control centre have complained of stress

The government, which owns about half of Nats, is discussing a proposed �65m investment from airports operator British Airports Authority (BAA).

The service is also awaiting a Civil Aviation Authority decision on its application to raise prices by more than inflation.

The Nats public private partnership was established when the government sold a 46% stake in the company to the Airline Group, a consortium of seven UK-based airlines (British Airways, Virgin Atlantic, British Midland, Airtours, Monarch, Britannia and EasyJet).

Last week the House of Commons transport select committee attacked the "cost-cutting and penny-pinching mentality" which threatened to do "terminal damage to United Kingdom's aviation industry and national interest".

In a report it said: "The weaknesses of the financial structure suggest a failure of due diligence at the time of the sale of Nats, when traffic was already declining and there were already moves towards the use of smaller aircraft."