He might not like Mondays, but it seems Thursdays are starting to annoy Bob Geldof too.

The singer, who was performing with his band, The Boomtown Rats, decided to lay into the crowd at a family festival in Brentwood, Essex. Their crime? Wearing Primark.

“F***ng Primark” to be exact.

“This is a rock’n’roll festival. When you come to a rock’n’ roll festival you dress for a rock’n’roll festival,” Geldof told his audience on Thursday.

And how exactly should one “dress for a rock’n’roll festival”? In a “mega” style, according to Blackrock’s finest.

“We are mega. And you are Brentwood. How do we know that you are Brentwood and we are mega? Because I am wearing a f**k off pretend snakeskin suit and [they] are wearing f**k off cowboy shirts even though they live in London.”

Unsurprisingly, the Essex crowd were having none of it and started to boo the old Rat before many walked out.

Things had begun badly when Sir Bob, as he is known to the British Royal family, began shouting and swearing as soon as he took to the stage.

He paused after just one song to bemoan Brentwood’s family festival for being “boring and tame”, according to one British paper.

“We don’t do Abba. We don’t do Robbie f***king Williams,” he told the crowd charmingly.

SOS, they probably thought, Geldof might have met his Waterloo here, but “Let Him Entertain You” and see how things go.

Festival co-ordinator Laurie Edmonds apologised for the language, after Geldof’s outburst, but said it all “part of the act”.

“They’re a punk band,”she told a reporter. “You expect them to be a bit controversial and he got a reaction from the crowd.

“There were still several thousands of people who stayed to the very end and were asking for encores.”

All good, clean fun, then. And when Bob Geldof cracks into his appearance fee, he might note that Primark does a nifty line in festival fashion. Show us the person at the Electric Picnic who hasn’t bought their wellies from Penneys and we’ll show you a liar.

According to therichest.com, Geldof (64) is worth about $150 million (€136million).

No wonder he doesn’t shop in Primark.