Boris Johnson is inspecting the new spectator stand and changing rooms at Streatham-Croydon Rugby Club, which have been built following a grant from his sports legacy fund.
The fund helps local clubs across the capital build new or refurbish existing sports facilities. The Mayor is meeting local youngsters who are benefiting from the new facilities.
The London Welsh rugby union team will find out next week whether their appeal against a five-point deduction and £15,000 fine has been successful.
An appeal hearing took place yesterday, over their punishment for fielding an ineligible player - New Zealander Tyson Keats - in 10 Premiership games.
Keats should have been eligible for an ancestry visa, due to his grandfather being born in England, but Mike Scott the former London Welsh team manager made a mistake in the original application.
Instead of reapplying, Scott told Keats' agent and the club that the visa had been successfully granted to the player. Meanwhile, Scott submitted false documents - including a forged passport - to the RFU in a bid to pass Keats off as English-qualified.
Scott has since been banned from rugby for life and cautioned by police for falsifying registration documents.
London Welsh argued they should not be blamed for fraudulent behaviour conducted by Scott, who was described in the original judgement as a "rogue employee".
The points deduction sent London Welsh bottom of the Premiership, two points behind Sale Sharks with five games left.
Braving rain and an extremely muddy pitch, the Prime Minister - who said he used to play the position of hooker - passed a rugby ball around with children who were having a taster session at Millwall Rugby Club in east London.
The Prime Minister has revealed that he played rugby with Olympics chief Seb Coe this morning at Millwall football club.
He quipped that it was "the only time I'm going to beat him in a race doing anything".
He is now unveiling new funding for more sports tuition in schools.
The London Welsh rugby union team will play in the Aviva Premiership next season after winning their appeal against a decision to block their promotion. The Rugby Football Union had decided the club did not meet the Premiership's standards but that has now been overturned.
London Welsh have beaten the Cornish Pirates 29-20 (68-41 on aggregate) to become the RFU Championship winners.
The Championship Play Off Final Second Leg at the Kassam Stadium in Oxford.
A cloud hangs over the Exiles victory after a RFU panel ruled they had failed to meet the minimum standards for promotion.
The Exiles have said they will fight the RFU decision "tooth and nail" after being "misled" over promotion.
The RFU argued that because London Welsh did not have “primacy of tenure” at the Kassam they did not fulfil entry criterion.
That's despite founder members London Wasps, London Irish, Sale Sharks and Saracens all playing at football stadiums where they do not control the fixture list.
England rugby captain Chris Robshaw is visiting his boyhood rugby club Warlingham RFC today.
He started playing at the club when he was seven years old and will be putting today's junior players through their paces with a special training session.