Slaughters' John Macaskill said: "The shape of this deal is interesting. Borrowers and savers who have been with the Bristol & West for less than two years will be getting preference shares in a Bank of
Ireland subsidiary. This is because of provisions in the Building Societies Act which restrict the payment of cash."
But Bristol savers of more than two years should be eligible for cash of at least £500.
Macaskill added the shape of the deal is not dissimilar to Abbey National's merger with the National & Provincial building society. Slaughters is advising N&P while Freshfields is representing Abbey.
Freshfields also scored a notable success when it was recently chosen to represent Newcastle-based Northern Rock building society, which is converting to a bank and looking for a quote on the London stock market in 1997.
Alan Newton, finance partner leading the firm's team in London, said he expects up to 10 lawyers on the Northern Rock team as work on the brief gets into gear.
The team also includes Edward Braham, Sue Porter, David Trott, Julian Makin, Jonathan Culshaw, Vincent Pollaers and Anthony Salz, who becomes senior partner in May.
One of the highlights of Northern Rock's conversion is a plan to create a Northern Rock Foundation which aims to apply for charitable status.
The foundation would receive 5 per cent of the converted group's pre-tax profits to show its commitment to the community in the north-east of England and charitable causes.