Yes in theory, but not easily. You would probably need to put up a false wall, something heavyish ( e.g. plasterboard ) to reflect sound back, and fill it with rockwool to attenuate the sound. It's necessary to avoid gaps and support the false wall in such a way as does not allow the sound to be transmitted via the supports. There was a query on I think, the 13th or 14th of August on this subject. If your mail programme deletes old mails you could search for it by doing a search on google, i.e +google +groups +uk.diy or somesuch. Sorry, no practical experience on soundproofing.
Andy