I found this while surfing...
By the winter of 1945/1946, the Brits debated if this formidable armada of enemy vessels was more of a liability than an asset. Many of the boats were in very poor mechanical condition, sorely in need of parts and maintenance. Most were made totally obsolete due to the advances made in their newer, faster, deeper-diving, quieter sisters. Considered of no practical value, the decision was made to scuttle them. Thus, in more-or-less random order, 121 captured U-boats were disposed of in a program known as Operation Deadlight. Towed in groups of six to ten to pre-arranged offshore dump sites well beyond the 20-fathom curve, the boats were scuttled with demolition charges. The bulk of the boats disposed of in this operation (93) were conventionally-powered Type II, VII, IXC and IXD hulks. Twenty-two of the fast new Elektro submarines and four of the larger XXI type were also scuttled in this manner. Last to be sunk in Operation Deadlight was U-3514, its sea valves opened on 12 February 1946.
All 32 remaining U-boats were eventually divided between the Allies as prizes of war. In this distribution, twelve units became British prizes. Eight of each went to the Soviets and France. Four to Norway. Some of these vessels were used briefly in research roles, others were eventually broken up as scrap or sunk as Naval targets by their respective owners.
I guess there was a lot of political reasons and mostly allied wanted to show people that justice always follows the sword of the winner! The value of the scrap metal is indeed interesting question...
