Request to remove comment of phone number

Received call today (15/11/13) from this number on my mobile. When I answered there was no caller on the line. Called back and call was answered with auto announcement without any ring tone. Queuing announcement 'your call is very important to us please hold the line for our next available agent'. My concern is this is some kind of scam designed to ramp up call charges when you call back etc although I think 0203 is a London code. This is very annoying and ofcom should act and stop this type of unsolicited call. Only thing I could do was add to blocked call list.