The end of the road for posters like this

And Rabbi David Lister, of Edgware United Synagogue, said: “My wife was driving and the kids saw it. We do not mind discussing this sort of thing in the proper way but it should not be splashed about in the streets.”

The JC’s calls to the 0800 number on the poster were not as illuminating as the 4ft high letters, however.

Asked to comment, an AMI supervisor said he could not because he was at the firm’s headquarters in Australia and said his boss was unavailable: “It’s 5am and he’s in bed.”

But he added: “Tell me what’s offensive about the word, sex? Look in your passport. You’ll see it written there.”

We called again a few moments later and asked to speak to the same supervisor. One of his colleagues said he was unavailable — but that they were both at a call centre in Twickenham.

A company spokesman later dismissed this as a “genuine miscommunication”.

The billboard (above), at Apex Corner, in Edgware, north west London, was part of a national campaign involving newspaper adverts and posters at 196 sites across the capital.

Titan Outdoor, which owns the billboards, said the ads would be removed by the end of the week following the public reaction. They had been due to stay until the end of the month.

But Dr Michael Spira, AMI Europe’s medical director, insisted: “We’re not out to offend anyone. The purpose of our direct advertising is to let men who are suffering sexual problems know that help is available.

“The billboards were never intended to be permanent or cause offence.”