The advert, previously run in October, was suspended soon afterwards as the ITC, the television watchdog, launched a detailed investigation into a number of complaints from broker organisations and other insurers. These complaints have now been largely rejected by the watchdog.
The TV commercial features a customer of an insurance broker struggling to deal with a car accident on a rainy day while a woman from Direct Line tries to persuade him that switching from his broker could make life easier and save him 15 per cent in premiums.
At one time such a scenario would have been difficult to argue with. Direct Line and other "direct insurers" - who deal exclusively over the phone and don't pay commission to intermediaries - enjoyed a clear edge in the motor policy market.
During the last two years, however, the gap has closed noticeably. Many motor insurance brokers now claim to outquote direct insurers on the majority of occasions and their claims are regularly borne out by research.
A recent mystery shopper exercise, albeit one commissioned by the British Insurance & Investment Brokers Association (BIIBA), compared the relative competitiveness of six brokers and six direct insurers - including Direct Line - over a range of motor risks. Brokers were found to be cheapest in five out of six cases. The same survey also compared efficiency and service levels and found that brokers enjoyed a marginal advantage over direct insurers.
But despite this and other evidence supporting the brokers' case, the ITC is allowing Direct Line to re-run its ad virtually unchanged.
Sharon Bolton, a director of BIIBA, says: "We find this whole business very disappointing as there is no doubt in our mind that this television commercial is very misleading. It gives the impression that Direct Line is 15 per cent cheaper across the board for motor insurance and we don't believe this to be the case."
For its part, Direct Line emphasises that its ad says that switchers "could save 15 per cent" as opposed to actually stating that it enjoys a 15 per cent advantage across the board.
The ITC justifies allowing Direct Line to continue to refer to 15 per cent premium savings on the basis of the evidence of a survey by the insurer into 2,000 of its own customers who had recently switched from brokers. They had enjoyed average savings of nearly 19 per cent.
But brokers reply that they can produce surveys of premium savings to be made from switching from Direct Line.
For example, Ipswich-based Colin Ryan Insurance Brokers claims that a random survey of 20 of its existing clients found that 16 - 80 per cent - were getting a better deal than they would have done through Direct Line. There was not a single case in which Direct Line's quote was 15 per cent less than Colin Ryan's own. And in eight cases it was at least 15 per cent more expensive - in two cases, 50 per cent more expensive.
The only allegation about the Direct Line advertisement that was upheld by the ITC was that viewers could be misled about claims handling services offered to brokers' customers. The advert implied that a broker's client would have to go to the trouble of finding a number of estimates himself and arrange for the repairs. In fact, the vast majority of brokers' clients now have access to a helpline or claims service for this purpose.
In the final analysis, whether or not TV adverts or counterclaims are overly selective or misleading, the main message to those buying motor insurance remains exactly the same: anyone seeking to find the best quote should shop around between a number of brokers and direct insurers, as none can guarantee to be the most competitive in every case.