The British Library's Colindale site closed in 2013, with the newspaper archive eventually planned to move to Boston Spa (but currently under embargo).
The BL now has a new online research facility for newspapers, operated jointly with DC Thompson newspapers (which, regrettably, means that it's a commercial service, charged at £12.95 for a month's access, although it's free to search and there's also a 48-hour pass for £6.95 - both of those also have a limit to the number of 'credits' available):
http://www.britishnewspaperarchive.co.uk/
However, despite covering 603 titles, not all newspapers are included and those that are may be limited to certain dates:
http://www.britishnewspaperarchive.co.uk/home/NewspaperTitles
You can also search for newspaper references via the main BL catalogue:
http://explore.bl.uk/primo_library/libweb/action/search.do?mode=Advanced&ct=AdvancedSearch&dscnt=0&tab=local_tab&dstmp=1457975965572&vid=BLVU1