Lotus is close to finalising a switch to Renault engines for next season - but the deal still depend on whether it can find an agreement with Cosworth to end its contract with the engine-supplier, two years before the contract end.

ALLSPORT understands that a deal has been agreed in principle for Lotus to secure a supply of Renault customer engines for 2011 – which would see the team receive the same specification of power-unit as other customer team, Red Bull Racing.

It is believed the move came out when Lotus originally sought out a new supplier of gearboxes and transmissions for next year – after frustrations with reliability in that area.

Renault was happy to supply its gearbox and transmission units ,but to increase its engine supply deals, it made a big effort to sell its power unit as part of the package too.

However, despite sources suggesting that a deal is ready to be signed for Lotus and Renault to tie up for the first time since 1986, Lotus still needs to resolve contractual issues with Cosworth, its current engine-supplier.

As part of the deal it made when it entered F1 this year, Lotus signed a fixed three-year contract with Cosworth – and it is believed there is no way back that would allow the team to get out of that unless the engine supplier was willing to do so.

It is not clear at the moment whether a financial settlement can be reached for Cosworth to agree to cut short its deal, or whether Lotus will be forced to delay its Renault ambitions.

Neither Lotus nor Cosworth have elaborated on the situation, and both insist that there are no plans for their relationship to change for now.