Vandalism of the Bomber Command Memorial in London has been described as “mindless” and a “disgrace” by Britain’s last surviving Dambuster.
White paint was thrown over the tribute in Green Park and a statue of Sir Winston Churchill in New Bond Street.
George “Johnny” Johnson said it was “disrespectful to the nearly 58,000 people who gave their lives.”
The RAF Benevolent Fund said it was the fourth time in six years the statue of air crew had been targeted.
The Metropolitan Police said it was investigating reports of criminal damage to a number of statues in London.
The memorial, which commemorates the members of Bomber Command who died in World War Two, was found sprayed with paint which was still wet at “daybreak” on Monday.
Mr Johnson, a squadron leader with the Dambusters who conducted raids on German dams in 1943, said he hoped those who damaged the statues “are caught soon, and suitably punished”.
The RAF Benevolent Fund said it estimates that repairs could run into thousands of pounds.
Air Vice-Marshal David Murray, the charity’s chief executive, said it was “the worst example of vandalism we have seen at the memorial”.
“This despicable act took just moments but will take considerable time and resources to put right,” he said.
Police are investigating the damage caused to the two statues, as well as reports of vandalism to the Canada Memorial in Green Park.
A spokesperson for the Met said no arrests had been made and officers were “working to establish whether the incidents are linked”.