British sports car manufacturer Lotus has boosted its workforce by 30% and is putting £20m extra investment into product development.

The carmaker, owned by Proton, has a five month backlog for the new Evora and has recruited 150 extra manufacturing staff in the last six months to cope with demand.

Evora is expected to sell more than 1,200 units annually and daily production will reach 10 cars by the end of November.

Lotus said demand for its small platform products, Elise, Exige and 2-Eleven, remained stable.

Investment for Lotus Cars will be in future variants of all Lotus products including an automatic gearbox version the Evora for the 2011 model year.

Research earmarked by Lotus Engineering includes range extender engines for series hybrids, lightweight vehicle structures, super-efficient internal combustion engines and hybrid and electric vehicles.

Lotus Cars director Luke Bennett said: "We must be one of the few car companies in the world that is increasing production and recruiting staff to support increased demand for its products.

"Lotus has not been immune from the effects of the global economic downturn, but fortunately we are better placed than most due to the timely launch of the new Evora."

It has also been confirmed that Lotus will return to F1 next year for the first time since 1994. It has been granted the 13th slot on the grid for the next season and they will be one of four new teams alongside Campos Grand Prix, Manor and US F1.