The answer isn't really a simple one.
Page 37 of this document shows the income and expenditure of HM Courts & Tribunals Service for the most recent financial year:
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/536077/hm-courts-and-tribunals-service-trust-statement-2015-16.pdf
You'll see that fines (approx £264m) only made up just over a quarter of the total income of around a billion pounds.
The 'disbursements' statement shows that quite a lot of the total revenue found its way to the Ministry of Justice and the Home Office (with an alarming £285m, which is more than the total income from fines, simply being written off as 'credit losses').
Once all of the expenditure and disbursements had been met, there was about £58m left over, which was paid to the 'Consolidated Fund':
http://www.parliament.uk/site-information/glossary/consolidated-fund/