[Mjb]

I assume it's an early termination clause or something similar. Often the contract is with a freelancer's limited company rather than a standard contract of employment.

Yes, he could have had an early termination clause, if another company came in with a higher salary. Especially if the last contract didn’t pay as much as was being asked for. His representatives could have asked for it to protect his earning potential if they thought the BBC weren’t paying what he could earn.

BTW if I remember correctly Ken Bruce didn’t complete his full contract and his show was finished a few weeks early. This would be quite standard when going to a competitor as to not finish on Friday and start at new station on Monday and take all your listeners with you. But would depend on the individual circumstances.