It sounds as if the wood in those areas was damaged by the cold, with some sort of rupture occurring, and infection has got in through the damaged areas. If the patches are widespread, and in particular on the main trunk, it may be best to remove it. If it starts 'bleeding' from any of those patches ( you can usually tell by dark staining in a run or drip pattern beneath the damaged areas) or develops obvious amber coloured resin deposits, remove as quickly as you can.

Do you mean remove the patches or the tree! If the patches, what do mean, without killing the tree?

No, I mean remove the tree.

Ive had a similar thing with a very large...probably 50+ year old Strawberry tree (Arbutus unedo) at work. I also saw a tree at Wakehurst place on sunday with the same.

I haven't had chance to have a good look yet but will make a point tomorrow.

It looks like areas of branches have been sprayed with a coppery orange paint....but only on the top of the branches eg the bit where the branches point upwards.

I'll try to get a pic tomorrow.

I've uploaded a photo for you to look at but from what you are saying it looks like it's for the chop - what a shame! Thanks for your help.

Can you point us to the direction of the photo ?

Looks like the tree photo has appeared next to this message. As you've probably guessed, I'm not sure how to send you a link but hope you can access the one here. Sorry about that!

Photo is in Nasko's gallery, Andy.
I can't think of any other explanation than the one I've given - at the moment, it doesn't look like canker, but clearly, you say your tree is dying back in some areas. If you want to try to save it, calling a reputable tree surgeon might be worthwhile, but if these orangey patches are on the main trunk and near the base, not sure what he can do. You could just wait and see what happens, removing any branches which are dying back, but keep an eye on the solidity of the tree by leaning on the trunk to make sure it's not getting wobbly in the ground. The last thing you want is for it to blow down in a gale...

The copper colour starts at the top of the trunk, goes up three branches and then down to about 2 1/2 foot from the base - it has travelled significantly in the last year. What's left of tree is in full flower at the moment. I live in Formby and normally we have very mild weather, however, the winter of 2010/2011 was very severe so I've always suspected that the damage to the tree stemmed from that. Tree surgeon I think! Thank you for your help.

A good one (tree surgeon) should know what's wrong and decide whether it needs to come out or not. Trouble is, there are so many new diseases affecting trees and shrubs now...

Laburnum are known as short lived trees 25-30 years. After 42 years it sounds as if yours may have come to the end of its life? The have shallow roots and have been known to topple over. Mine seems fine this year but the flowers are late.