Businesses in a tower block in Croydon are vowing to physically stop a mobile phone company from putting a mast on top of the building next door amid fears it could damage their health.

The owner of Albany House and the businesses which rent office space there plan to physically block the path of a crane which the mobile phone company want to use to access the land and put up the transmitter.

Mobile phone company Hutchison 3G submitted plans last August to place a 6.5 metre transmitter, disguised as a flag pole, on top of 88-90 South End next door to Albany House.

Croydon Council says 160 letters were sent to addresses closest to the site and less than five objections were received. As a result the mast was approved at the end of August.

Anita Bishop, who owns Albany House, objected to the application. She said: "The company putting up the mast want access to my land to move a crane. There's no way I'm going to let them through. If this is the only way I can stop them from putting this mast up, so be it."

David Gregory, owner of Brickworks Marketing Communications, says he will cancel his tenancy and take his business elsewhere if the mast goes up.

He said: "I am not convinced these things are harmless. I won't put myself at risk and I won't put my staff at risk. I believe that transmitters are detrimental to your health, that your immune system is considerably weakened by them."

A spokesman for Hutchison 3G said: "We understand the concerns raised. However, there is an increasing demand for this kind of technology not least from businesses".