(Reuters) - Google apologized on Monday for allowing ads to appear alongside offensive videos on YouTube as more high-profile firms such as Marks &amp; Spencer and HSBC pulled advertising for British markets from Google sites.<div><a href="http://feeds.reuters.com/~ff/reuters/technologyNews?a=Y6J4X53-fcI:f4mxyIdow5A:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/reuters/technologyNews?d=yIl2AUoC8zA" border="0" /></a> <a href="http://feeds.reuters.com/~ff/reuters/technologyNews?a=Y6J4X53-fcI:f4mxyIdow5A:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/reuters/technologyNews?i=Y6J4X53-fcI:f4mxyIdow5A:V_sGLiPBpWU" border="0" /></a> <a href="http://feeds.reuters.com/~ff/reuters/technologyNews?a=Y6J4X53-fcI:f4mxyIdow5A:-BTjWOF_DHI"><img src="http://feeds.feedburner.com/~ff/reuters/technologyNews?i=Y6J4X53-fcI:f4mxyIdow5A:-BTjWOF_DHI" border="0" /></a></div><img src="http://feeds.feedburner.com/~r/reuters/technologyNews/~4/Y6J4X53-fcI" height="1" width="1" alt="" />