Don’t mention the War ... Unexploded bomb from the Blitz shuts down former London mayor Boris Johnson’s flagship East-West Cycle Superhighway

“Don’t mention the War,” goes the line from Fawlty Towers. Foreign Secretary Boris Johnson ignored that sage advice on Wednesday. And, irony of ironies, the following day, his flagship East-West Cycle Superhighway was closed thanks to an unexploded bomb dropped by the Luftwaffe during the Blitz.

Following Prime Minister Theresa May’s confirmation on Tuesday of a Hard Brexit, Johnson provoked outrage across Europe when, during a trip to India, he fired a warning on Wednesday at French President, Francois Hollande.

"If Monsieur Hollande wants to administer punishment beatings to anybody who chooses to escape, rather in the manner of some World War Two movie, then I don't think that is the way forward,” he said.

"I think, actually, it's not in the interests of our friends and our partners."

Memories of World War Two were evoked closer to home on Thursday evening when an unexploded bomb was pulled from the river by a Thames dredger, just a few hundred yards from the Houses of Parliament.

Hours of traffic chaos ensued as Waterloo and Westminster bridges were closed while Royal Navy bomb disposal experts dealt with the wartime ordnance, as was a large stretch of the Cycle Superhighway on the Embankment.

Royal Navy bomb disposal experts detonate German bomb found in the River Thames last night https://t.co/NcdlE8hWvj pic.twitter.com/IGjemp2FRi

— Royal Navy (@RoyalNavy) January 20, 2017

Johnson – no stranger himself to comparisons with Basil Fawlty, even before this latest gaffe – officially opened the first stretch of the East-West Cycle Superhighway on his final day as Mayor of London in May last year.

> Boris Johnson opens Cycle Crossrail in final act as mayor

The following month, he helped the Leave campaign secure a narrow victory in the referendum over the United Kingdom’s membership of the European Union.

Despite Johnson's well-catalogued series of foot-in-mouth comments over the years about other countries, May appointed him Foreign Secretary after she succeeded David Cameron as Prime Minister in July last year.

Shortly before leaving City Hall last May, Johnson said that pushing through the Cycle Superhighways was the most difficult thing he had done in politics.

Responding to Baroness Jenny Jones at Mayor’s Question Time in November 2015, he said: “I can’t think of anything I’ve ever done that’s provoked such direct remonstrances from everybody.”

There are likely to be a good few people in the UK and beyond who, 14 months on, could make other suggestions.