Shares in Bradford & Bingley (B&B), the UK's biggest buy-to-let mortgage lender, plunged this morning after it announced a shock profits warning while planning a £300 million rights issue, and confirmed that TPG, one of the world’s biggest private equity firms, is to take a 23 per cent stake in the group for £179 million.

What shall shareholders and customers do in the light of today's news?

B&B's share price has fallen by more than two thirds in the past six months - and by 40 per cent in the past month alone. In an effort to raise much-needed capital, the bank launched a rights issue, in which extra shares are issued and offered to shareholders at a reduced price.

Shareholders were told Initially that the reduced price for each share would be 82p but this has been cut to 55p, and forced B&B's shares to a record low of 60p this morning.

Keith Bowman, equity analyst at independent financial adviser Hargreaves Lansdown, said: “Whether or not shareholders will want to take up these reduced shares depends on their portfolio. Those whose portfolio is heavily weighted towards banking may think it is time to diversify; on the other hand, you may consider this a bargain buying opportunity.

“TPG is investing £179 million in B&B and this must be seen as an expression of confidence in the bank – although remember private equity firms are in the business of taking high risks. B&B is heavily reliant on the mortgage business and its future will very much depend on how the UK’s property market fares. If the market deteriorates drastically over the next two years, it will make life very difficult for the bank.”

I have a B&B deposit account. Are my savings at risk?

B&B has offered attractive savings rates in recent months as it tried to attract deposits to boost funding. Those lured by its best buy rates – such as its fixed rate Isa at 6.25 per cent – may now be worried, particularly in the light of what happened at Northern Rock.

But financial advisers say there is no need to panic.The Financial Services Compensation Scheme guarantees deposits of up to £35,000 with a financial institution. This means that in the unlikely event of a bank or building society collapsing, the first £35,000 helf with that bank will be covered.

Kevin Mountford, head of savings at comparison service Moneysupermarket.com, said: “A number of banks are suffering at the moment but, as far as B&B is concerned, TPG's interest could be seen as a positive and an indication the worst is behind it.

“That said, consumers will understandably be wary. Anyone with concerns would be wise to spread funds across a range of savings brands to ensure no more than £35,000 is invested with a single provider."

Remember that "financial institution" refers to each banking group, not individual brands. So, for example, the FSCS would only cover £35,000 of savings held with HBOS, which owns Halifax, Bank of Scotland, Birmingham Midshires, AA and Saga.