Adverse litigation experience has forced one of the biggest names in "after the event" legal expenses insurance, Abbey Legal Protection (ALP), to implement a massive hike in premium costs.

From the beginning of November, cover for road traffic accidents will increase from £92 to £148 while cover for other injury cases will more than double from £155 to £315.

ALP, with around 80% of the market, provides insurance cover to offset the downside of legal cases brought by conditional fee solicitors though its Accident Line Protect scheme. The company's "Protect" policies are available to personal injury litigants fighting their case with the help of conditional fee solicitors, and who wish to insure themselves against receiving a massive costs bill if they lose the case.

Solicitors can insure on behalf of their clients for cases up to a value of £15,000.

The company said a key reason for the premium increase was adverse selections by solicitors choosing to insure risky cases while claimants with good prospects of winning or receiving a favourable settling were not insured.

The scenario, which Abbey says it has tackled by tightening the rules, has had a negative effect on the scheme's predicted results.

The company declined to say what percentage of "after the event" personal injury cases had gone sour.

Since the inception of the scheme four years ago, ALP has covered more than 67,000 after the event personal injury cases of which approximately one third have been settled.

The price changes are based on an audit of cases settled, representing around one third of the total covered.

"The message we need to get across is that there is no such thing as certainty in legal cases," said Abbey Legal Protection managing director Chris Ward.

"The most professional lawyer in the world cannot possibly foresee every eventuality such as an unexpected judgement or an unreliable witness.

"Since we have been running the scheme we have see many such cases," he added.