President John Evans Atta Mills, returned home on Sunday night after a three-day official visit to the United Kingdom at the invitation of British Prime Minister, Gordon Brown.Briefing journalists on arrival, Mr Mahama Ayariga, Presidential Spokes person, said President Mills held discussions with British officials on the strengthening of bilateral ties between the two countries and co-operation in trade and investment.He said they also held talks on the need for the two countries to collaborate against cross border crime and development assistance from UK to Ghana.Mr Ayariga said President Mills held discussions with some investors and invited them to Ghana to explore the investment opportunities in the country.President Mills visited the London School of Economics, met the Ghanaian community in the UK and reiterated his commitment to the rule of law and reach out to all and sundry to build a government of unity.Accompanied by his wife, Naadu and some government officials, President Mills was met on arrival by Vice President John Dramani Mahama, Ministers of State, Major General Peter Blay, Chief of Defence Staff and Mrs Elizabeth Mills Robertson, Acting Inspector General of Police.Source: GNA