A second UFO sighting in the skies over Streatham and the curious disappearance from YouTube of the original video footage have fuelled speculation that something strange is going on.

On Tuesday night at around 10.30pm Gary Richardson, 42, was out walking his dogs when he saw a UFO displaying unusual-shaped lights slipping silently over Mitcham towards Streatham, before suddenly disappearing.

Three weeks ago TV editor and sci-fi fan Mark McConnell called the Guardian newsroom reporting that he had seen a similar object, three lights giving off a dull glow, hovering 200ft over St George's hospital on the night of August 14.

Mr McConnell managed to video what he saw and loaded it onto the internet site YouTube so people could make up their own minds.

But shortly afterwards the video disappeard from the site.

When we contacted him to ask why it was no longer up Mr McConnell claimed it was a simple mistake - although it is difficult to delete videos from the site accidentally.

He said: "There's no reason, I was just tidying up my website for work. I'll put it back up for you."

Mr McConnell expressed his delight at the second sighting, saying: "It's absolutely excellent that someone else has seen it. I told you it's out there.

These are not the first sightings in the area. According to previously secret Ministry of Defence documents released by the National Archives last month, there was a rash of UFO sightings in London in 1993 and 1994, including in Wandsworth and Streatham.

In November 1993, there were dozens of sitings of a brightly illumnated oval object flying above London. A top-secret internal MOD memo from the time reads: "A lady phoned about a UFO in Streatham. She described it as a spaceship - bright silver moving very slowly."

The official explanation at the time was that the object was in fact a Virgin airship advertising the launch of the Ford Mondeo.

Mr McConnell has now put his video back on You Tube

so judge for yourself whether you think aliens are really visiting this part of London. And have you seen anything suspicious? Leave a comment below.