Bob Bell believes Renault faces a lengthy period of catch-up in Formula 1 after returning to an Enstone team he claims has been "starved of resources".
Following a period with Manor last year as a technical consultant, Bell left the team in November ahead of a third spell at Enstone, with Renault confirming his position as chief technical officer at its launch event on Wednesday.
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In light of what he has encountered, Bell concedes it will take time for Renault to build up its personnel and facilities following its acquisition of Lotus in December.
"It is a question of playing catch up," said Bell.
"Enstone has been starved of resources for at least the last year, for good reason - and I'm not being critical.
"It means the head count has dropped, physical resource, capability has dropped, whether that's maintenance, machine tools, test rigs.
"It hasn't been possible to keep all of that side at the highest level.
"So for Enstone, particularly in the short term, it will be about building that resource base back up and getting it fit for purpose again.
"Fundamentally the structure is sound, and there is a very good nucleus of people to build on."
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Facing a staggering loss of nearly £65million in 2013, Lotus was forced to make a significant number of staff made redundant, along with other cuts across the board.
Its cause was not helped by the takeover talks with Renault that began last summer, resulting in all development being halted on the car.
It means Renault goes into this season on the backfoot, and looking at a two-year plan to be in a position where it can challenge at the front.
"The guts of it should be done in a two-year programme," added Bell.
"So it will be this year and 2017 before we are pretty much at a level we think you can realistically compete and be in the top three. We are not going to be rushed into this.
"It is very definitely the case we accept Renault is in for the long haul, so we are not going to go out and grab the first person that comes our way, if you take the recruitment of new people for example.
"We are going to try and choose the best we can, and if we have to wait for them, then we will wait for them."
Bell concedes the plans will be gradual, with steps taken over the course of this year and 2017 to ensure Renault is in a healthy situation for '18.
"This year can be characterised as stabilising the situation, and laying some of the very basic foundations for the future," said Bell.
"Next year is about showing a step forward in capability and performance, obviously.
"Then 2018 is really about having a very credible target for the team, and a performance step that will demonstrate Renault is back and is a very serious competitor again."