Advertising claims made by Direct Line that its roadside rescue service has “one of the fastest response times in the business, averaging 33 minutes” and that it fixes 80% of vehicles at the roadside have been shot down by the Advertising Standards Authority (ASA).

The advertising standards watchdog has upheld a complaint from rival roadside rescue firm the Automobile Association (AA) that Direct Line's claims were not substantiated by its own data.

As a result, the ASA has advised Direct Line to consult its committee of advertising practice copy advice before advertising again.

Direct Line said its response times claims were supported by internal data collected between May 1998 and August 1999.

However, the ASA said it was concerned that Direct Line had omitted to include data for the period between September 1999 and the time of the adverts publication. The ASA said it understood Direct Line had changed its network of mechanic operators in this time and customers had a right to expect the claims to reflect up-to-date service levels.

As a result, the ASA concluded that Direct Line had not proved its claims were statistically accurate and upheld the AA's complaint.