David Walliams gathered his strength this morning for the final day of his epic 140-mile Thames swim – as his mother hailed him ‘the nation’s sweetheart’.

The Little Britain star made an early start in order to beat the tide and is due to complete the swim at around 6pm in central London.

Thousands of cheering fans greeted him on Sunday night as he made it to Teddington Lock after a 21-mile stint – his longest day so far.

To date, his extraordinary efforts have raised more than £900,000 for Sport Relief.

As well as the aches and pains of carving through the water from Lechlade in Gloucestershire to the edge of London, he has also battled diarrhoea, vomiting and low energy levels from ‘Thames tummy’.

He has also struggled with a painful rash where his wetsuit has rubbed his neck. He had initially planned to do the journey in trunks, but the cold meant he needed further protection.

His mother, Kathleen, said: “I feel people think they’re part of this because they can actually see him doing it.

“He’s the, sort of, nation’s sweetheart because he’s doing this – rescuing dogs along the way and waving to people when all he wants to do is lay down almost. I’m very, very proud of him.”

Walliams, 40, said of the support he has received: “I never expected this to catch the public’s imagination like it has – there seems to have been a real carnival atmosphere around it which is lovely.”

Supporters can sponsor the performer at www.sportrelief.com/walliams.