Williams: Pat Symonds to leave as chief technical officer

Symonds, pictured with Williams deputy team principal Claire Williams, has spent 25 years in Formula 1

Williams are to part company with chief technical officer Pat Symonds.

The 63-year-old, who joined the team in 2013, is "stepping down at the end of 2016", the team said in a statement.

Symonds' departure precedes the expected arrival at Williams of Mercedes executive director (technical) Paddy Lowe, who is to join next season.

Lowe's departure - from the team whose technical side he has overseen for three consecutive world titles - has not yet been officially confirmed.

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Williams paid tribute to Symonds for his efforts in "overseeing a strong turnaround in the team's performances on the race track".

Williams finished ninth in the constructors' championship in 2013, followed by third in 2014 and 2015, and fifth this year.

Mercedes executive director (technical) Paddy Lowe is expected to join Williams next season

Symonds has been in F1 for 25 years and won a total of four world titles with Michael Schumacher at Benetton in 1994-95 and Fernando Alonso at the team's successor Renault in 2005-6.

But he was also found guilty for his part in fixing the 2008 Singapore Grand Prix in the 'crash-gate' scandal and was banned from F1 for five years.

He returned as a consultant for the Marussia team - now Manor - before joining Williams.