The government will have to renew its support for airlines lacking cover for war and terrorism risks, according to aviation industry experts.

They have estimated UK airlines are losing the equivalent of $250m (£173m) a year due simply to the impact of the 11 September attacks on insurance premiums.

The figure includes premiums airlines have to pay to the government as well as higher rates for commercially available cover.

Under a current temporary deal the government acts as insurer of last resort.

The cover has been extended twice, but will expire at midnight on 22 January.

The EU has effectively sanctioned the government's stance until the end of March when similar agreements end in Japan and the US.

Roger Wiltshire, general secretary of the British Air Transport Association (BATA), which represents most of the UK's scheduled and charter airlines, predicted the government would have little option but to extend its current agreement.

"I don't see any chance that the UK will be able to stop [the arrangement] at that point."

Association of Insurance and Risk Managers executive director David Gamble said airlines needed stability.

"My members would like to have a confirmed situation really for a 12-month period."