Why isn't England's cable network open to competition ?

Recently I received my last phone/cable TV/broadband Bill. It was over £80 for one month !

Over the last year, since I last phoned NTL Virgin to try to prune some of the cost the Bill has risen from about £50/month. I'm just back of the phone after talking to some phone operator in India about reducing the set of services I receive again. I think I've reduced by Bill to about £35/month, but we'll see.

Why stick with Virgin Media ? Well their cable modem service has been good over the last few years, and we can't get reliable TV reception. But it occurs to me that I should have more of a choice. Surely Virgin should be forced to open its network to competitors, just as BT has been forced to do ?

I know Richard Branson has good relations with the Labour government, but isn't it time the free market arrived for cable customers also ? ( OK I understand the original argument about needing to get a return on laying the cable network, but the time period for this is long past ).

I wonder what ofcom are doing about this ?