(Adds analyst comment, background)
LONDON, Sept 8 (Reuters) - Shares in Edinburgh-based LloydsBanking Group and Royal Bank of Scotland fellon Monday after supporters of Scottish independence took theirfirst opinion poll lead since the referendum campaign began.
Lloyds' shares were down 2.5 percent by 0845 GMT and RoyalBank of Scotland's down 2.3 percent. Shares in TSB, which does aquarter of its mortgage lending in Scotland and ismajority-owned by Lloyds, were down 2.8 percent.
Scotland will vote on Sept. 18 whether to stay in the UnitedKingdom.
Economists have questioned whether an independent Scotlandwould be able to host such large banks. Banking industry sourcestold Reuters last week that Lloyds is considering moving itsregistered offices to London if Scots vote for independence. RBSis examining its options.
The two banks have warned that Scottish independence wouldpresent a significant risk to their businesses, impacting theirfunding, tax and compliance costs.
Analysts at Credit Suisse said that a vote for independencewould result in complex legal issues and additional costs forboth Lloyds and RBS, whose registered offices are in Edinburgh.
They also said a "yes" vote could complicate theprivatisation of Lloyds and RBS. The government pumped acombined 66 billion pounds ($106.7 billion) into the banks tokeep them afloat during the 2008 financial crisis.
The British government holds a 25 percent stake in Lloyds,having sold 13.5 percent of the shares over the past year andhad hoped to sell more this month if Scots voted againstindependence. Those plans will be put on hold if there is a"yes" vote.
The government also holds an 81 percent stake in RBS whoseshares are trading below the price it paid for them.($1 = 0.6186 British Pounds) (Reporting by Matt Scuffham; Editing by Laura Noonan and JaneMerriman)