I have never given notice/resigned.How do you go about giving notice? Do I just send an email, or post a letter?And what should the content say?Thanks

http://www.i-resign.com/uk/letters/letters.aspNormal circumstances in big 4 is to send an email to your performance manager (meet him/her first let them know your intention) who will kick off the leaver process by submitting the neccessary forms to HR. Just copy/paste/edit one of the templates in the link above to suit your exit strategy.

Send a letter confirming a) your resignation, and b) your final day. Nothing else is required.If they demand that you stay on to complete your project, then tell them that it's hard cheese. If they wanted security, they should have included a longer notice period in the contract.And get references from clients, not the former employer.