Regarded as one of the ugliest men imaginable and, using the title of Duke of Cumberland, he married Princess Thyra of Denmark, the youngest sister of Queen Alexandra of Great Britain and Empress Marie of Russia. Ernst August and Thyra became the parents of six children.

The Hannover family was affected by th enactment of the Titles Deprivation Act, which was passed by the British Parliament in November 1917, to deprive those peers and princes who were Britain's enemy during the war. A Privy Council report said the "names of such person, if he be a peer, shall be struck out of the Peerage Roll, and all the rights of such peer to receive a writ of summons to sit in the House of Lords or take part in the election of representative speers shall cease and determine." The report also stated that "all privileges and all rights to any dignity, whether in respect of a peerage or under any Royal Warrant or Letters Patent, shall cease and determine."

The names of three peers, who were deprived of their British titles, appeared on the Privy Council's Order on March 28, 1919: Prince Ernst August, Duke of Cumberland and Teviotdale; the Viscount Taaffe of Corren; and Prince Charles Edward, Duke of Albany. Prince Ernst August, who was also the Duke of Brunswick-Lueneburg, was given the right to petition for the restoration of his British titles.

The Act did not deprive the Duke, a great-grandson of King George III, of his title, Prince of Great Britain and Ireland, nor the qualification of royal highness, to which he was entitled as a prince of Brunswick. Nor did he loose his right to succeed to the British throne, although this was largely a moot point due to the number of Queen Victoria's Protestant descendants alive in 1919.

Source: Leo van de Pas