post-christmas lull  in lending uk mortgage lending showed a  post-christmas lull  in january  indicating a slowing housing market  lenders have said.  both the council of mortgage lenders (cml) and building society association (bsa) said lending was down sharply. the cml said gross mortgage lending stood at £17.9bn  compared with £21.8bn in january last year. the bsa said mortgage approvals - loans approved but not yet made - were £2bn  down from £2.6bn in january 2004.  at the same time  the british bankers  association (bba) said lending was  weaker . overall  the bba said mortgage lending rose by £4bn in january  a far smaller increase than the £5.1bn seen in december. this was a return to the  weaker pattern  of lending seen in the last months of 2004  the bba added. however  it is the year-on-year lending comparisons which are the most striking. the cml said lending for house purchases and gross mortgage lending were 29% and 18% lower year-on-year respectively.  these figures show beyond doubt the recent slowdown in the housing market   peter williams  cml deputy director  said.