Actor David Walliams has fallen behind schedule in his charity swim of the heavily polluted river Thames because of "Thames tummy".

The Press Association reports that Walliams has suffered a high temperature, vomiting and diarrhoea but has managed to raise over £200,000 for Sport Relief in three days.

He said: "I always knew there was a risk that taking in the water could cause problems, but now it's happened it's still hit me really hard. I was sweating in the night and have been to the toilet a lot this morning.

"When I heard the total raised had jumped to more than £200,000 it gave me a real boost, as do the thousands of people who have been turning out and cheering. There were so many last night I thought Take That were in a boat behind me.

"This is already much harder than I thought it would be - but this Thames tummy I've got is making the task seem incredibly difficult and London seems a long way away."

Walliams intends to swim over 140 miles in eight days from Gloucestershire to London.