Sterling hits 2-1/2 yr low vs dlr on fresh bank stress

* Sterling hits 2-1/2 year low vs dlr at $1.7322 GBP= * Banking sector woes dominate on talk of funding for RBS

* UK industrial output data adds to poor economic picture

* RBA 100 bps rate cut builds talk of decisive BoE action

By Veronica Brown

LONDON, Oct 7 (Reuters) - Sterling slid to 2-1/2 year lows versus the dollar on Tuesday, as a fresh bout of fear blew through stock markets with reports that the UK government could be forced to provide funding for Royal Bank of Scotland (RBS.L).

RBS shares fell almost 40 percent at one point and were last down 30 percent on the day at 103.9 pence, with Lloyds TSB (LLOY.L) and Barclays (BARC.L) also losing ground after the BBC said the three big banks had asked the Treasury for 15 billion pounds each.

The chief executive of RBS (RBS.L) declined to comment on what he described as speculation of any action the UK government might take to help banks, including talk it might inject capital [nWLB2092].