If this wasn't so serious an issue it would be funny....
Long store cut short, a client had a penalty on their website so they decided to stop using the .com and use the .co.uk instead. They got the .com removed from Google using webmaster tools (it had to be as it was ranking for a trade mark they didn't own and there are legal arguments about it)
They launched a brand new website and placed it on both domains with all seo being done on the .co.uk. The web developer was then meant to put the rel=canonical on the .com pointing to the .co.uk (maybe not needed at all thinking about it, if they had deindexed the site anyway). However he managed to rel=canonical from the good .co.,uk to the ,com domain!
Maybe I should have noticed it earlier but you shouldn't have to double check others' work! I noticed it today after a good 6 weeks or so. We are having a nightmare to rank the .co.uk for terms which should be pretty easy to rank for given it's a decent domain.
Would people say that the rel=canonical back to the .com has harmed the co.uk and is harming with while the tag remains in place? I'm off the opinion that it's basically telling google that the co.uk domain is a copy of the .com so go rank that instead.
If so, how quickly after removing this tag would people expect any issues caused by it's placement to vanish?
Thanks for any views on this. I've now the fun job of double checking all the coding done by that web developer on other sites!