Dennis Delderfield (b. 1926) is the leader of the New Britain Party, Delderfield is also a member of the Springbok Club and is involved in a number of bodies within the Church of England. He recently been involved in an employment tribunal with St Bartholomew the Great on its ex-verger's behalf, but was replaced by the person he represented and was described by counsel at the hearing that concluded the case (in the Church's favour) as 'entirely negligent'. Delderfield became rich as a result of his ownership of a number of local newspapers in England, including the City of London and Dockland Times, although this only publishes sporadically now, (and is a tabloid in nature and content) and through trading in the City. Formerly a member of the Court of Common Council of the City of London, he lost his place when declared bankrupt in 1995.

On 24th February 1977 Delderfield stood in the City of London and Westminster South by-election. Peter Brooke was elected with 11,962 votes and a majority of nearly 8,000. Delderfield polled 306 votes, 143 behind the Pro-Homosexual Civil Rights candidate. In the 1983 General Election he contested the Kent Mid constituency and polled 324 votes, 0.68% of all votes cast. The Tories won with 25,400 votes and a majority of 12,543. Delderfield came fourth out of four and lost his deposit. Delderfield's most recent electoral outing came in the General Election of 2001 when he stood in the Bethnal Green and Bow constituency. He secured 888 votes, which represented a 2.3% share for that constituency. His party has since declined from its 1977 peak and he is the sole party member. The NBP is an anti-immigration right-wing party, described as "as an avowedly racist far right party" by the Observer in May of 2001.

Candidates in the 2001 General Election had to declare their election expenses. 3,319 candidates contested seats at the election — 28 failed to submit election expense returns. Delderfield was one of them and his name appears on the defaulters list of the Electoral Reform Society.

In the May 2002 local elections Delderfield and another NBP candidate contested the ward of St Katherine’s & Wapping: Labour won the three seats, and Delderfield polled 259 votes. Not deterred, he stood in a by-election held in the ward of Blackwall and Cubitt Town on 27 June 2002, and effectively deprived the Tories of a victory. Labour won by ten votes — 686 to the Tory 676: Delderfield polled 19.

In his publication New Britain he declared that he would be standing for Mayor of London in the 2004 election and that the NBP would have a list of candidates for the GLA. The declared policy would be: “To abolish the office of a Mayor for London and the Greater London Assembly because it is a waste of public money and duplicates a system that is already in operation.” (New Britain, July/August 2003) In the event, Delderfield did not stand and no NBP candidates were fielded.

He has recently taking a leading role in campaigning against attempts to involve Spain in the running of Gibraltar and is a leading advocate of Britain leaving the European Union and concentrating on the Commonwealth of Nations.