Overdraft suddenly removed

Just got a message saying my overdraft will be removed in a month. Which is a bit puzzling because its not for a lot (£250) and I've never used it in the 5+ years I've had the account.

I also have a business account with Starling where my small businesses cashflow is kept, which has a fairly large balance.

No debts except a mortgage and no missed payments

Anyone have any clue why they removed the overdraft ?