Overpaid by work issues

Goddamn idiots at work paid me for the time I was doing Jury duty despite me telling them at least seven times that I was doing Jury duty and filling in a loss of earnings form from the court. Now I've been paid for a full month's work as well as the equivalent I should have lost from the court so I'm several hundred quid up.

Stupidly I decided to wait till after the weekend to tell anyone what had happened, went to London, got absoulutely off my face, decided to spend a stupidly large amount of money I didn't really have, had a f*cking brilliant time but now I don't really want to give the money back as I could really do with it. Now, every day that goes by takes me further away from being able to realistically own up and claim the time lapse between me geting paid and telling them about it was down to me not checking my bank statement.

Essentially, I'm thinking of just keeping quiet about it and claiming I thought that was what was supposed to happen if I get called on it but it's leaving me with some pretty thorny ethical issues to grapple with, besides the obvious stresses about what happens if I do get busted. I actually really hate my job but the money's good and I could do without the stigma of getting sacked for something like that on my CV or my family, friends or colleagues finding out.

So does anyone have any experience of something like this? Am I worrying over nothing or being a thieving b*st*rd? And who exactly am I robbing here? The taxpayer or my employers (who, let's be clear about this, had ample warning about what was happening and insisted I claim the money from the court, tight fisted scumbags as they are)?

Apologies for turning up here out of the blue with my troubles yet again but I can't really discuss this with anyone and would really, really appreciate some friendly advice.  

That's what I was thinking of doing to be honest but it still feels a bit wrong. I'm just going to take the line that it's my employers who are out of pocket as opposed to taxpayers to help me get over the "scrounger's guilt". It's their fault for not doing their jobs properly. Is it just where I work or are all HR departments this f*cking useless?

Thanks for the advice though. I can't really talk to anyone I know about this in case someone lets it slip to the wrong person so it's good to finally ahve someone else echo what I was thinking. Very reassuring.

In my last job i was almost double paid one month. I thought it was me finally getting my tax back after filling out all the relevant forms at work, but it turns out it was an admin error, which i only found out after going on a monumental weekend of debauchery and materialism. The overpayment was taken out of my next wage, which left me with £350 for a whole month. Basically, if you owe them money as an employee, they'll have a policy somewhere for the repayment. Best best is to speak to your line manager and see if you can extend it. Play the financial hardship card if need be.