It could be worse, you could've been stopped by the police for a random check on the way back from drawing out a rather sizeable lump of cash and then have them 'steal' it because they didn't believe you'd be able to withdraw that amount, despite you having a receipt from the bank in the same bag and on top of the cash. So rather than simply believing him and phoning the bank in question to sort it out in minutes, they decide to 'steal' the money under the proceeds of crime act and then arrest you on suspicion of money laundering.
Happened to the Father of friend of mine. He'd arranged with the bank beforehand to withdraw such a hefty sum (£75k) and had to travel to a large branch to actually pick the money up, it was on his way back from that branch that the fun started. Even when it was finally sorted out the next day it took him ages to get the cash back.
Yeah the proceeds of crime act is basically guilty until proven innocent.