http://www.sfla.co.uk/divorceprocedure.htm
Filing the petition to divorce
Having established that you have the requisite grounds for divorce, you can now proceed with filing the petition to divorce. It is at this stage you’ll need to think about speaking to a divorce solicitor. Essentially divorce in England Wales is not an onerous matter, as, in most cases, the emotional turmoil means that the parties agree that divorce is the only option left to them. That said, you will need to speak with a solicitor if (a) children are involved; or (b) you have significant joint assets.
To file the petition itself, you’ll need to complete the official Form D8 (or D8A in the case that you have children) in triplicate – one for you, one for the court and the third is sent to the other party. The D8 forms are then submitted to the relevant county court.