By Kylie MacLellan LONDON (Reuters) – Britains GCHQ intelligence agency said on Tuesday it would start to share classified cyber threat information with private companies amid concerns over increasingly sophisticated targeting of businesses by hackers. Britain regards cyberspace as a top-tier national security priority and key sectors, including finance, energy and transport, have been told to improve their defense against disruption to essential services by hackers. GCHQ, the British equivalent of the United States National Security Agency (NSA), said on Tuesday its director, Iain Lobban, would announce the information-sharing deal – initially on a pilot basis – at a two-day conference on cyber security being hosted by the intelligence agency in London. GCHQ will commit to sharing its classified cyber threat information at scale and pace to help communications service providers protect their customers;