Millward played in the 1967 Test Series against the Kangaroo tourists in Britain, and the 1968 World Cup, both campaigns being unsuccessful. However, his finest hour as an international came in the Great Britain touring party of 1970. He was overlooked in favour of former Castleford club mate Alan Hardisty for the first Test against the Australians. The Great Britain team was heavily beaten 37–15 and wholesale changes were made for the 2nd Test. Millward was drafted into the side, where he gave a superb match winning performance scoring 20 points (2 tries, 7 goals) in a 28–7 win to square the series. This equalled the match points record for an individual against the Australians, which had previously been set by Lewis Jones.