The incident at around 7 o’clock this morning caused delays of five miles.
Two lanes were shut between junction 12 for the M3 and 13 for Staines to repair the defect.
A spokesperson for National Highways said:
“We are sorry to hear of this incident and the inconvenience and concern it will have caused.
“When potholes do occur we repair them as soon as possible, and we are presently in the process of a repair to be carried out as soon as possible.
“Our comprehensive maintenance and renewals programme, which we operate across all of our major roads and motorways, helps to minimise the risks of potholes occurring but it can’t eradicate them.”
“Safety is National Highways top priority, and on dual carriageways like the M25 we carry out a rolling programme of safety inspections to maintain our roads in a safe condition while causing minimal disruption for road users.”