MAYOR of London Boris Johnson will roll up his sleeves and help plant thousands of new trees in one of the borough's most popular parks this week.

He will be joined by Redbridge mayor Jim O'Shea and around 100 volunteers at Roding Valley Park in South Woodford on Wednesday (January 12).

The event is part of RE:LEAF London, a campaign to plant 20,000 new trees across London, which is being run in conjunction with the charity Trees for Cities.