TORONTO, July 23 (Reuters) - Toronto's main stock index fell sharply on Monday, led by mining and financial shares, as investors fretted about an escalation of Europe's debt crisis after it appeared Spain may have to seek a full sovereign bailout and on renewed fears about Greece. The Toronto Stock Exchange's S&P/TSX composite index was down 169.37 points, or 1.5 percent, at 11,453.54. At one point the index touched 11,448.50, its lowest level since July 13.