£25 gets you one of these
And an hour or so putting it into any bit of clothing you want gives you lovely toasty feelings
Steptoe has a kit sewn into some leggings and a top......I've just got one sewn into a fleece waistcoat.....ten times better than the old BMW waistcoat I wasted money on and 8 times cheaper
The best bit is that 'cos you do it yourself, you can add it to any item of clothing you want, whether it's an existing inner lining or a fleece top or whatever.....and you can concentrate the heat anywhere you like so if you have a long back (like me) you can put a few extra feet of the wire there.
I also put a double loop around the collar of my flece waistcoat to keep the neck warm
Thoroughly recomended and at that price, you don't have much to lose
http://cgi.ebay.co.uk/Heated-Jacket...ameZWDVWQQrdZ1QQcmdZViewItem#ebayphotohosting