What are the millions FOR?

As the Prime Minister's collar gets itchier with the slow but sure approach of Inspector Plod, I am increasingly puzzled by the glaringly obvious but unasked question: What do political parties need these huge sums in donations or "loans" for? They must, of course, maintain a central party organisation and staff, and they require an election campaign fund, much of which will presumably be spent [wasted?] on expensive advertising. But millions? Surely not.

In my politically active days, the Conservatives mostly financed their constituency parties locally, with such modest events as bring-and-buy sales and garden parties. Labour depended on trade union support, provided [while it existed] through the political levy. The Liberals, as they usually did, lived from hand to mouth.

So what has changed to make it necessary for political parties to require such lorryloads of cash? Answers on the back of a postcard, please. You just might get a peerage in the resignation honours which will shortly be issued from Wormwood Scrubbs.