[3][7] After the 2008 presidential election, President John Atta Mills appointed him Minister for Health in his government in February 2009.
[6] Following investigations conducted by the Serious Fraud Office of the United Kingdom, Mabey and Johnson Limited, a supplier of steel bridging based at Twyford, Berkshire was prosecuted in 2009.
[9] Yankey denied these allegations in a statement issued after Mabey and Johnson had been fined £6.6 million by the Southwark Crown Court.
His resignation was accepted by President Mills, who in addition, invited the Commission on Human Rights and Administrative Justice to investigate the case.
In his role he was responsible for leading the company and building the infrastructure for sustainable gas distribution across Ghana.