Supermarket sandwich maker Greencore has agreed a £1.2 billion takeover deal for rival Bakkavor in a move that will create a food-to-go giant with around 30,500 staff.Under the cash-and-shares deal, Greencore will pay £2 a share for Bakkavor, which it said is a 33 premium on Bakkavor’s closing share price on March 13.The tie-up – structured as a reverse takeover – will form a combined food group with annual sales of about £4 billion which supplies many of the UK’s biggest supermarkets and retailers.