Last October's Paris motor show saw Lotus reveal one of the most ambitious rebirth plans the motor industry has ever seen. Five all-new cars, starting with an Esprit supercar in 2012 and finishing with the Eterne saloon, with Elise, Elan and Elite models in between. For these cars, all created from idea to full-size mobile model in just nine months, new design chief Donato Coco had to invent an entirely new Lotus look, light, airy but aggressive. Big names from high-end car companies came on board. It all seemed too good to be true.

Critics were quick to identify the snags, one of the main ones being that however good the Toyota-based engines, part of  new Lotus-Toyota deal forged around the Evora, might be, they don't suit a £100,000 supercar such as an Esprit. Buyers expect something bespoke. Lotus was defensive about this, but in a set-the-record-straight session on December 15 at London's RAC Club, its three most influential executives revealed some more of Lotus's plans.

CEO Dany Bahar agrees about the engine-pedigree snag. The engine, he says, is the heart of the car and if Lotus is to be a credible supercar manufacturer, able to line up against Ferrari, Lamborghini and Porsche, it must have its own engines. 'We have the knowledge to make our own,' he says, 'because we already design engines for clients.'

The will is there, but the business case has to stack up. 'We're doing the sums now, and we'll know by the end of January. If we go ahead, the new Esprit [due in 2012] will have our own V8, and a V6 engine will be derived from it. There will be an element of hybrid drive, because a Lotus has to be efficient. In fact all the new Lotuses will have a degree of hybrid technology, from simple stop-start and energy recovery in the Elise to electric motors for the front wheels in the high-end cars, giving virtual four-wheel drive.'

That will still leave the four-cylinder engine for the 2015 Elise, and Lotus has already hinted that it might not be Toyota-powered. News of Lotus's tie-up with Renault for Formula One suggests possible Renault power, reprising the use of a Renault engine in the original Europa and a Renault gearbox in second-generation Esprits, and Bahar doesn't deny this.

Which leads to what will happen in next year's F1 season. The problem is that the Renault deal was sealed well after Group Lotus licensed the use of the Lotus name to Tony Fernandes' Team Lotus operation, which took to the tracks in 2010 and, like Group Lotus itself, is Malaysian-backed. It's a tricky situation, but Bahar felt the opportunity to run with a 'top five' F1 team was too good to miss and ultimately Lotus owns its own name. Proton, Lotus's parent company, also has a design and engineering tie-up with the Renault-Nissan Alliance: 'We had already spoken about engine manufacturing,' says Bahar, 'and then Formula One came up.'

Next year we'll most likely see four Lotus-badged F1 cars on the grid because contracts will make any other outcome unlikely, but thereafter the current Team Lotus will probably gain a new name. 'It's nobody's mistake,' Bahar insists, 'and it's not really a fight. I am not the bad guy here – you wouldn't believe how many boards and committees are involved in this.'

Returning to the planned road cars, Dany Bahar confirmed that the new models would also spawn lightweight, stripped-down 'R' models with more power – such as an Elise with 350bhp. Lightness is to remain a key Lotus feature, with the next Elise remaining under 1000kg despite being able to accommodate heftier people and being much easier to enter and exit. The Elise R's target mass is 950kg, and even the V8 Esprit should weigh no more than 1350kg.

New engineering chief Wolf Zimmerman, late of AMG where he was behind the Mercedes SLS among others, elaborates on the weight issue. He says the Evora is too heavy, and while Lotus will continue with bonded-aluminium structures they will in future be made from 7000-grade aluminium instead of 5000-grade. The new metal is stronger so each section can be thinner. Some sections will be hydroformed. Higher-end Lotuses will use some aluminium body panels too, supplied by either Magna or Thyssen-Krupps, both of which are tendering for the job.

Which illustrates another key part of the new Lotus strategy. 'Part of the reason for our Paris presence was to show suppliers that we'll be a company with sufficient volumes to be worth dealing with,' says Bahar. 'This has been difficult for Lotus up to now, but in the future we'll be dealing with the big names.'

One example is interiors, never a Lotus strong point, which will in future be made by the same German supplier as used by Porsche and Audi. Another is electronic architecture, doing away with the old-fashioned wiring harness still used in today's Lotuses and replacing it with a modern multiplex and data-bus system. The Evora will be first to see these changes, in the next model year, so the much-reviled red instruments, unfathomable switchgear and clunky sat-nav will go.

Dany Bahar's intention is that Lotus will be profitable in five years' time. To launch five new cars in that period is a big undertaking, but not as big as it first seems because much is shared between them under the skin. 'It's really two-and-a-half cars,' he says. 'Making a five-car range is a more expensive route but it opens more doors.' The hope is that all will be built at the Hethel factory, which is undergoing a revamp with new production facilities and an updated test track, and 1200 jobs will be created provided Lotus can get the government loan it needs.

'It will be a loan, not a grant,' Bahar insists. 'A grant suggests that the company is not sustainable, and we want to prove that it is.'