A Home Office investigation into a sex for visas scandal at Croydon's Lunar House immigration centre has been launched.

A former Lunar House employee claims officials at Britain's busiest immigration centre slept with attractive girls desperate to avoid being kicked out of the country.

And speaking exclusively to the Croydon Guardian a Lunar House insider said he is shocked by the allegations but not surprised.

The insider said: "There are so many different departments within Lunar House and we don't have much contact with each other so I can see if something like that did happen that it would be easy to get away with.

"Things are so detached from each other at Lunar House that I suppose something like that would be easy to get away with because people are not likely to find out."

Despite the severity of the allegations, the insider said the scandal has not really been discussed in his department.

"We've read the newspapers and listened to the news but the whole place is so disjointed that no one talks to each other, but I think most people are just trying to get on with their jobs the best they can.

"But it has been a big shock and people are disappointed with the allegations and if they are true it is sad that people should be allowed to get away with that sort of thing.

"When you think about how isolated Lunar House is it's feasible that this sort of thing could happen.

"It is not transparent enough here, it's run by just a few people. Hopefully things can change for the better in the future."

An investigation was launched after a former employee claimed he regularly saw colleagues give out phone numbers to attractive immigrants and that those they thought were ugly risked having their applications rejected.

The man also said those they rejected for being unattractive had their pictures pinned on walls so people could laugh at them.

The shocking claims, which this week sparked an immediate probe by immigration top-brass, also said pretty girls would be seen within minutes while other migrants would be left queuing for hours.

The 23-year-old man, who worked at Lunar House for four years, said he left his job in disgust at the behaviour of his colleagues and after his complaints of the alleged corruption had been ignored by the Home Office.

Croydon South MP Richard Ottaway called for a thorough independent investigation into the allegations. He said: "This is the most degrading form of corruption one can imagine. I call on the minister to investigate this to the highest level and to make a full statement to the House."

Home Office Minister Tony McNulty said: "I have every confidence that staff within the Immigration and Nationality Directorate carry out their roles with professionalism and integrity.

"There are clearly established systems for staff to raise any concerns that they may have with working practices within their team and to take the issue further if they feel it is necessary.

"These are serious allegations and I will ensure that they are fully investigated. Until the outcome of that investigation is known, it would be inappropriate for me to comment further but clearly I will not condone this type of behaviour among staff."