To petition for divorce in England or Wales you MUST file your original marriage certificate or a certified copy.

If you were married in England or Wales ONLY you may obtain a copy certificate online on the website of the General Register Office - www.gro.gov.uk

Alternatively you may usually obtain a copy at the place where you were married whether that is a church or a register office. Some venues may not keep certificates and some may simply have closed down (for example a hotel). In that case you will have to apply to the General Register Office.

If you were married abroad, you will have to make enquiries at the place where you were married and if that is not successful then request more information from the relevant consulate.

The General Register office will charge you £9.25 for it's standard service which takes up to 15 days.

They also operate a priority service which costs £23.40

More details can be found on the government website www.direct.gov.uk