Martin Whitmarsh's future as McLaren Formula One team principal was in doubt on Thursday with the announcement that his predecessor Ron Dennis was replacing him as group chief executive.

In what some saw as an internal coup, McLaren said in a statement that the 66-year-old Dennis was effectively regaining overall control of the former world champions he ran from 1982 to 2009.

The Briton will combine Whitmarsh's duties as Group CEO with his existing role of Group chairman and head of the McLaren Automotive sportscar division.

Dennis, who presided over some of the greatest years in the team's history with champions such as Ayrton Senna and Alain Prost, had relinquished his role of Group CEO in 2012 but had increasingly chafed at the team's poor performances on the racetrack.

The team's last championship was with Lewis Hamilton in 2008 and they have not won a constructors' title since 1998.

McLaren endured a dismal season last year, failing to finish on the podium for the first time since 1980. Jenson Button's fourth place in the final race of the season in Brazil was their best result.

The team will be powered by Mercedes this year but will be renewing their partnership with Honda in 2015 and hoping for a return to former glories.

Speculation last month suggested Dennis, who has a 25 percent stake in McLaren, wanted to regain control and replace Whitmarsh as principal.

There has also been speculation that Ross Brawn, the former Honda and Mercedes principal who left the latter team at the end of last year, could be lured to McLaren.

Brawn won the 2009 championship with Button and his own Brawn GP team, which rose from the ashes of Honda after the Japanese manufacturer quit the sport at the end of 2008, that is now Mercedes.

The burly Briton has also been linked to a technical role with the governing FIA.

"I want to clear my mind, take a rest and then decide if I want to return to F1, subject of course to any opportunities existing," Brawn told the BBC last month.

In a 20-minute address to assembled McLaren employees at the Woking factory, followed by a long ovation according to one of those present, Dennis assured them that "there will be change" and also that "we will win again".

Whitmarsh's future was not mentioned in the McLaren statement, and he was not present at the address, but an announcement is expected next month on the future leadership.

"During February I will articulate a new Group strategy and implement the organisational structure best suited to achieving it," said Dennis in the statement.

Sources indicated that there had been no change of shareholdings at McLaren, which is half-owned by Bahrain's investment fund Mumtalakat, and nobody had been sacked or made redundant.

However the statement quoted Dennis as saying the shareholders had mandated him to "write an exciting new chapter in the story of McLaren, beginning by improving our on-track and off-track performance."

He said that over the coming weeks he would be undertaking a "thorough and objective review" of all the McLaren businesses.

With the Scot having already lost his Force India seat, it was announced on Tuesday that Paul di Resta is returning to the German touring car series DTM in 2014.

The 27-year-old entered F1 in 2011 as the series' reigning champion, and he is now returning to Mercedes, for whom he raced throughout his four-year DTM career.

And there are reports di Resta could combine his racing duties with a formula one role with Mercedes' works Brackley based team this season.

"It is emerging that Mercedes may ask di Resta to act as reserve driver for their F1 team, which will make him back-up to Lewis Hamilton and Nico Rosberg," the correspondent for the Times newspaper, Kevin Eason, said.

Di Resta will kick off his DTM return immediately, with a test beginning on Tuesday.

"It feels really good to be back in the DTM and to see so many familiar faces again," he said.

After a period of intense speculation, Caterham on Tuesday finally announced its all-new race lineup, thereby completing F1's field of 2014.

As expected, the Tony Fernandes-led team said returning Japanese driver Kamui Kobayashi will be joined by Swedish rookie Marcus Ericsson.

Also as reported earlier, Dutchman Robin Frijns, who worked in a similar role at Sauber last year, will be a new Caterham reserve driver.

"The process may have taken longer than we'd have liked, but we didn't want or need to be rushed into such important decisions, and we have been in the happy position of having a wide range of drivers to choose from," said team boss Cyril Abiteboul.

Japanese Kobayashi, renowned for his adrenaline-fuelled driving style, thanked his fans who pledged money to help the popular 27-year-old return to F1 after losing his Sauber seat in 2012.

"I am very pleased that the money they raised not only helped me but will now go to helping Caterham progress this year," he said.

What is also clear, however, is that drivers with more lucrative backing were overlooked by Caterham.

"This wasn't about money," said team owner Fernandes. "Having him here is a good morale boost for the team."

Entrepreneur Fernandes, who also owns the Malaysian airline Air Asia, hinted that 2014 could be Caterham's last chance to score a point and move up the F1 grid after three years as a backmarker.

"There comes a point," he admitted to Britain's Sky.

"I'm the most optimistic man in the world but you don't want to be coming last all the time. This is a very pivotal year."

The reigning champion team had only managed to complete three laps on the opening day on Tuesday because of delays caused by a part being fitted incorrectly ahead of its first run.

Its hopes of getting valuable mileage under its belt on Wednesday were then dealt a blow when Vettel was confined to the pits by what is understood to be a Renault energy store issue early in the afternoon.

The team elected to abandon its running for the day so Renault could be given more time to look into the problem and sort a solution for Thursday.

Vettel has canceled his media commitments for Wednesday evening and will fly home. His new team-mate Daniel Ricciardo will take over for day three as scheduled.

Vettel's issue comes amid a difficult start to the week for Renault, whose mileage has lagged behind its rival engine manufacturers. With just over than two hours to run on Wednesday, Mercedes had completed 115 laps with its teams, Ferrari has managed 56 while Renault had done just 11.

Red Bull's pre-season struggles continued as the world champions endured a difficult third day of testing in Jerez.
The car broke down on its first lap in Daniel Ricciardo's hands after Sebastian Vettel managed only 11 laps over the first two days.
Ricciardo had to wait for three hours while problems with the hybrid energy recovery system were fixed.
The car then ground to a smoky halt on the Australian's first lap.
Red Bull said the latest problem was the team's responsibility, rather than that of their engine partner Renault.

Ricciardo went out again about half an hour later but by the midpoint of the day he had completed only two laps under the car's own power.
The team were later forced to call off any running on Thursday, making it a total of 13 laps achieved by the car over three days so far.
Red Bull's junior team Toro Rosso, who also have a Renault engine, were unable to run at all on Wednesday.
Their driver Jean-Eric Vergne had completed 22 laps by 13:00 local time on Thursday, four hours into the eight-hour test, but was 20 seconds off the pace set by Jenson Button's McLaren-Mercedes.
Renault's third team, Caterham, were also struggling with what they said were "software problems", and reserve driver Robin Frijns had managed only eight laps.
The lack of mileage for Renault-powered cars compared to those of rival manufacturers Mercedes and Ferrari continued a trend since the beginning of the test and is a major concern for the French company.
Button's fastest lap of one minute 25.030 seconds in his McLaren was 0.465secs quicker than the Ferrari of Fernando Alonso.

The Spaniard, cheered on by hundreds of fans in the grandstands at the Jerez track in southern Spain, also suffered a breakdown mid-morning, before resuming running a little later on.
Lewis Hamilton's Mercedes was third fastest, half a second slower than Alonso and more than a second ahead of the next car, the Williams of Alonso's former Ferrari team-mate Felipe Massa.
The Marussia team have yet to run at all. Their car only arrived on Wednesday afternoon and the team are still preparing it in their garage. English driver Max Chilton said he expected to drive in the afternoon.
The test continues until 16:00 GMT on Thursday, with the final day on Friday.