Subscriber numbers at BT’s (NYSE: BT) mobile phone business have hit an all time low, calling into question the company’s plans to use mobile services to help shore up revenues. The Timesonline.co.uk reports that BT currently has a mobile phone subscriber base of 86,000, less than half of its all time high of 187,000 in 2005, shortly after the company first began revealing figures for the mobile unit.

Previous media reports have said the company is working on a new strategy which could involve a mobile device that would allow consumers to access emails and the internet. The Times adds that it may also involve BT’s broadband offering, and customers may have to buy it and the mobile service together. CEO Ben Verwaayen has ruled out any purchase of a mobile company to boost the unit.

The disappointing mobile service subscriber figures comes just weeks after BT quietly announced it would no longer be marketing its mobile-WiFI combination service BT Fusion to consumers in order to rework its mobile strategy. Three years after its launch, BT Fusion has only attracted 45,000 subscribers. The service allows consumers to make mobile calls off Wi-Fi connections at home and at BT hotspots around the country. It switches to Vodafone’s network when neither of these two options is possible. The service is similar to T-Mobile HotSpot @Home service in the US.

BT’s struggles in the mobile space have been blamed on its lack of its own network (it piggybacks on Vodafone), and from other mobile phone companies luring customers from its traditional base of landline users. According to Ofcom, there are now just as many mobile-only households in Britain as there are fixed line-only ones.