Angus Rigby replies:
There is no central place to find all this information, but I can suggest a number
of websites that you might find useful.

The Building Society Association website provides some useful information on
the takeovers and flotations of building societies, along with a ‘Where is my building society now?’ search facility. Visit the website www.bsa.org.uk/consumer/factsheets/.

Information on the history of banks, including takeovers and mergers, can usually be found on their individual websites. Some charting packages, such as those provided by Digital Look, can be used to gauge the impact of a takeover or merger on a company’s share price, by allowing you to display the timing of significant events on a historic share price graph.

Finally, your broker, or the London Stock Exchange, should be able to provide historic prices and a news archive of UK-listed companies.