Sharia law is widely applied in UK, not officially but among the Muslim community themselves in considering family disputes etc. No Stoning, no cutting off of hands just simple justice practised by people judging problems as they see them with God's help as they believe. No legal status but effective in removing women from unhappy marriages, settling inheritance issues etc. A cheap and effective way of solving peoples problems without the ruinous cost of court cases involving lawyers.
The effect is the same as an arbitration, cheaper and if accepted by the parties,effective. Remember disputes leading to lawsuits are generally based on prejudice, remembering all the instances of the other parties guilt and bad behaviour and forgetting your own.

These Guys who advocate such things as the March 4 Sharia are sociopaths, no good sending them somewhere else, still couldn't fit in any society hence Al Qaeda in Afghanistan and now Pakistan attacking food aid workers and bombing mosques in complete complete defiance of Islamic teaching, why don't more Muslims condemn this in the same way as huge numbers in the West protested the Iraq war?