Paddy Lowe, McLaren's technical director, will not travel to Melbourne with the team for the opening Formula One race of the season on 17 March and will join Mercedes at the end of the year.

Last month, the Mercedes team principal, Ross Brawn, responding to questions about his own future with the German team, categorically denied Lowe would be joining as long as he remained in charge.

He said: "Paddy is not coming. I want to see how things go before I make a final long-term commitment. If I choose to leave the team then Paddy will come. We've got a plan. We have a fall-back plan. It's as simple as that."

But Lowe's move to Mercedes is a done deal with McLaren announcing on Monday he will be replaced with Tim Goss. Lowe will join Lewis Hamilton in time to oversee the massive changes for 2014, when the engines will downsize from V8s to V6 1.6 litre turbo charged units.

Lowe's arrival will not necessarily lead to Brawn's departure. It now seems that tensions between Brawn and the team's new non-executive chairman, the occasionally fractious Niki Lauda, have eased under the calming influence of Toto Wolff, who joined Mercedes as the director of motorsport from Williams at the start of the year, replacing Norbert Haug, and has since battled to establish stability. That has been his repeated theme. Wolff recognises that his arrival, together with that of Lauda and Hamilton, has created enough turbulence at the team's Brackley headquarters.

Lowe will continue to be employed by McLaren through 2013, in accordance with his contract. But he is not expected to be seen around the team and "will be performing a different role" within the organisation, according to the team principal Martin Whitmarsh, albeit undefined and understood to be away from grands prix weekends. The last thing McLaren want is Lowe taking their secrets to Mercedes.

However, the future of Brawn will remain the subject of speculation. He will be 60 next year and unless Mercedes make significant progress by then he is likely to move on, with Lowe taking charge of operations.

Brawn is a wealthy man. He has also enjoyed monumental success, first with Benetton, then Ferrari and then with his own Brawn GP team, which Mercedes took over at the end of 2009. He has nothing to prove.

When Mercedes moved in, Brawn and the chief executive officer, Nick Fry, sold their shares. Lauda's share ownership amounts to 10%. But Wolff, with 30%, is the dominant figure.

The departure of Lowe is another blow for McLaren, who had already lost their star driver, Hamilton, to the same team.McLaren are under immense pressure to produce this year after a disappointing season in 2012. They started and finished 2012 with the quickest car, which was also often the best in the course of the season.

They also had Hamilton, the fastest man in F1 and driving at the peak of his powers. Yet they contrived not to win either the drivers' or the constructors' championship and also to lose the services of the man who remains the sport's top box-office attraction.

McLaren also have a headache with their engine supplier, Mercedes. Next year Mercedes, making their own engines, will have a massive advantage and so will Ferrari and Red Bull (Renault).

McLaren will consider another engine option in 2014 or 2015. And that could well mean a return to Honda, renewing a partnership that served them so well in the era of Ayrton Senna and Alain Prost.