Thanks for the clarification.If in your shoes I would do the following (in this order):1) Confirm how much holiday leave you have used/remaining.2) Sign and return the contract for the new job and make sure you have a copy of it.3) Hand in your resignation letter in person. Keep the letter very brief and formal. Make sure the letter is dated, state that you are giving notice with effect from that date, and request to forfeit your notice period. This would allow you leave immediately without breaching your contract. The reason for handing over the letter in person is so you can briefly explain to your manager that you have an opportunity to start elsewhere immediately, wish to take it and reassure them that you will be able to make suitable provisions to enable someone else to take over your work (NB. this has to be true to work).4) Confirm your departure date. If your request to leave immediately is turned down, you can still request to put your remaining leave towards an earlier departure date. Again, you remain within the terms of your contract but can leave earlier. Get your departure date in writing.5) Confirm your start date for the new firm. Although you'll technically still be under contract with your old employer for the period when your holiday leave is in effect, you should be able to start your new job during that time without any problems.* Leaving in an amenable manner is the best idea, even if it is very tempting to ditch the job asap. The idea is not to burn bridges - for example, even if right now you can't imagine wanting to come back, the people you work with could transfer to the new firm and end up working with you again.* It's also important not to breach your contract because references generally will check your last two employers as a matter of course. So when you move on from the firm you are going to now, a diagreeable departure could come round and bite you.* Sounds obvious, but make sure you get everything in writing, from both your old and new employers, to avoid getting caught in the middle.* Here's how the holiday thing works if it's not clear. Assume you have a 25 day per year holiday entitlement, a holiday year running 1/1-31/12 and haven't used any of this year's entitlement, then assume that you resign tomorrow (so your contractual last day is 20 May). 4.333 months worked /12 months in the year x 25 days annual entitlement = 9.72 days holiday you can ask to take off your effective departure date. That's pretty much two weeks (10 working days) so you halve your notice period.