Nick Clegg visited a Glasgow dogging site while he was Deputy Prime Minister.

The Lib Dem leader was in the city for his party’s annual conference in 2013.

While there aides decided he would announce a key environment policy at a local nature reserve.

But while scoping out the Cathkin Marsh site with local police they were alerted to another use for the beauty spot.

Staff immediately panicked and wondered whether to find an alternate venue.

But within hours they discovered news of the announcement had leaked and they would have to bring the planned press conference forward, leaving no time to find another place.

Ben Rathe, who used to work for Mr Clegg, confessed what had happened on his personal blog.

One policeman told him it was an “interesting place for a visit,” Mr Rathe wrote.

“I, thinking he meant they usually take politicians to schools, factories or nursing homes, launched into an explanation about why we’d chosen this location, the environmental impact discarded bags can have etc etc. I was swiftly cut off.

“’No, I mean because of what the locals use it for,’ he said.

“Now, 'what the locals use it for' is never a good sentence to hear, because usually 'the locals' are never using ‘it’ for anything good.

"I didn’t want to ask what he meant, mainly because I knew what he was going to say if I did, but felt that I had to. So I did.

“And then came the reply I had both expected and dreaded.

“’Oh, it’s a dogging site.’”

Just weeks earlier two pensioners had been spotted engaged in an “unsavoury act” in the bird hide at the spot on the outskirts of Glasgow.

A spokesman for the Lib Dems said: “As media coverage of the event shows it was the perfect spot, being a well-known nature reserve, to launch our policy."

He added: “Whatever people get up to in their own time, is up to them.”