ADSLGuide reports that BT's division for managing the local loop, Openreach, has changed its policy towards the DACS line sharing device. Due to cost reasons lines with DACS on had sometimes prevented ADSL being installed, yet this is no longer to be the case:

Previously if you ordered broadband, or a new PSTN line with the requirement for broadband, any line sharing device would only be removed if the cost to do so was under £1000. NOTE: This refers to cost to Openreach, not a price that was ever charged to the member of the public.

A new policy has been circulated to members of the Openreach division, that it will now remove DACS units for broadband order, if a PSTN line is ordered specifically for broadband use, or is an LLU order, even if the cost is over £1000 per line.

It's unclear how many people/exchanges could benefit from the move, although any positive step like this is generally a welcome one.