McLaren engineering chief Paddy Lowe has revealed that the number of wheel tethers on cars will be doubled from next season.

First introduced in 2005, wheel tethers, which had a minimum load of six tonnes, were the result of research carried out by the newly-established FIA Institute for Motor Sport Safety.

Since their introduction they have proved their worth on a number of occasions, however, more recently there have been a number of incidents in which the current specification clearly wasn't strong enough. As a result, the Technical Working Group has agreed to introduce a second tether connecting each wheel to the chassis.

"Wheel tethers are a great concern to us," he told reporters in the latest McLaren Vodafone phone-in press conference. "We had the tragic incident last year with Henry Surtees, and we also see wheels coming off F1 cars rather more often than we'd like and than the rules intended when tethers were introduced. They are working but they're not reliable enough.

"What we found is that when they don't work they have been cut for some reason due to the nature of the accident," he continued. "Our thinking is that if you put two tethers on each corner that are run independently we're going to drastically improve the probability that one or both tethers survive in an accident."