A littering fine can range from �50 - �80 depending on the Authority issuing under the Environmental Protection Act 1990 Section 87.
There is a period that some authorities will allow a reduction in the amount for an early payment, for example our authority give out an �80 fine payable in full within 14 days which, if paid within 10 days, is reduced to �50.
Unless the officer issued your 'friend' with a legal Fixed Penalty Notice (FPN) then this does sound very strange.
An FPN may only be issued if the officer feels that they would have enough evidence to take the matter to magistrates court if the fine is not paid and in this case, without showing that they actually issued your friend with a fine stating where to make the payment and how, I cannot see how this would ever stand up in court and would be questioning the authority before making payment.
Our authority do not allow its enforcement officers to accept payment in any way shape or form which takes away the situation that you have just explained and the possibility for accusations of theft.
Ask the question from the local authority!!! It may be that this guy is not an authorised officer for the purposes of litter and that he is simply going around collecting money from people who fall for it!
Hope this helps
Cheatseeker!