The reductions vary depending on the mobile network being called and the time of day.

BT calls to mobile phones will be cheaper in future

For example, the weekend rate for calling Cellnet numbers from a BT line will go down to two pence a minute.

A BT spokesman said: "The new lower prices reflect lower costs and reduced payments that BT has agreed with Cellnet and Vodafone following last year's enquiry by the Monopolies and Mergers Commission (MMC)."

The wide variation in price reductions reflects the termination rates that BT is charged by the mobile operators.

The termination rates are set independently by the mobile operators themselves.

Reconnection fee waived

BT also announced earlier this week that it has scrapped the £9.99 reconnection charge for residential customers.

Taking over an existing BT residential line will now be free - even if there is a break in service.

At the same time, BT is cutting the cost of installing a completely new residential line from £116.33 to £99.00.

Bill Cockburn, group managing director of BT in the UK, said: "This is great news for customers wanting to come back to BT. These changes will also make it cheaper for those who have never had a telephone to get on our network."