Just bought 30 second class stamps and sent a parcel recorded delivery in the Post Office. The stamps cost £6.30 and the recorded delivery costs £2.25.

‘That will be £8.55, please Sir’.

I hand over a 20 pound note. The lady gives me £8.55 in change, asks me to put the parcel in Santa’s overflowing grey sack and prepares for the next customer.

‘Sorry but I thought you said it was £8.55’

‘Yes. That’s correct.’

‘But you only gave me £8.55 change’

‘Yes. That’s right’

‘But it should be, err, 11 pounds, err, 45 pence’

‘No. It is 8.55’

‘How much are the stamps and the recorded delivery ?’

‘8.55’

[People are now starting to sigh loudly in the queue]

‘How much did I give you ?

‘Twenty pounds’

‘What is 20? minus? 8.55 ?’

‘Oh I see. I am awfully sorry, Sir.’