sentences:  Mack unsuccessfully contested the Wallasey constituency at the 1929 general election and at the 1931 election.He did not contest the 1935 general election, but in 1942 he was elected unopposed at a by-election on 11th March in the Newcastle-under-Lyme constituency.The seat had been vacated when the sitting Labour MP Josiah Wedgwood was elevated to the peerage.