The head of a far-right group within the RF, he called for Rhodesia to abolish black representation in parliament and adopt "a form of political apartheid".

[3] When the Prime Minister Winston Field resigned in 1964, Harper was a front-runner to succeed him, but lost out to Ian Smith, who moved him to the Ministry of Internal Affairs.

In 1966, when Smith brought a working document back from the HMS Tiger talks with the British Prime Minister Harold Wilson, Harper led opposition to the terms in Cabinet, contributing to their rejection.

He subsequently became a vocal critic of the Prime Minister, greeting each step Smith made towards settlement with black nationalists during the Bush War with public indignation.

He destroyed another Bf 110 over Dunkirk three days later, during the evacuation of Allied forces, and continued as flight commander until 8 June 1940, reverting to the rank of flying officer.

Four days later, after taking off as part of a group of six Hawker Hurricanes assigned to intercept more than 20 Luftwaffe aircraft, Harper contacted the German planes alone and probably destroyed a Bf 109 before being shot down.

[4] Harper was appalled when Britain made India independent in 1947—he held that the British government had unnecessarily caved in to Indian nationalist demands and should have continued in the subcontinent indefinitely.

[21] Amid decolonisation and the Wind of Change, the Federation was looking ever more tenuous and the idea of "no independence before majority rule" was gaining considerable ground in British political circles.

[26] When black nationalist riots broke out in the townships in October 1960, Harper condemned the Southern Rhodesian Prime Minister Sir Edgar Whitehead and the governing United Federal Party (UFP) as too lenient on the protesters, and argued that giving concessions following political violence would make black Rhodesians believe that "trouble pays dividends".

"[28] In 1962 Harper was a founding member of the Rhodesian Front (RF), an alliance of conservative voices centred around the former Dominion Party and defectors from the UFP.

The party's declared goal was independence for Southern Rhodesia without radical constitutional change and without any set timetable for the introduction of majority rule.

[30][31] Over the next few years, Harper became one of the main agitators in the Cabinet for a unilateral declaration of independence (UDI); equating Southern Rhodesia to India, he saw this as a way to prevent a repeat of "the same mistake".

Harper, described in The Spectator as "an ambitious politician and single-minded upholder of white supremacy", was generally considered the more hardline choice, and the man more likely to go through with UDI.

[36] As Minister of Internal Affairs, Harper oversaw the indaba (conference) of chiefs and headmen at Domboshawa in October 1964, at the end of which the tribal leaders unanimously announced their support for the government's line on independence.

During Smith's negotiations with the British government, each breakdown or setback was accompanied by speculation in Rhodesia ("Southern" was dropped in late 1964) that Harper might step up to take his place.

"[2] While insisting that Rhodesia would continue regardless of international opinion, he publicly demonised the UK government, describing it in January 1966 as "an enemy ... [that] must be brought down".

[45] Although Harper was considered an intelligent and capable minister by peers and reporters—a 1965 report in The Economist called him "by far the best brain" in the Rhodesian Cabinet[46]—his views were often perceived as overly reactionary.

When Smith brought a working document back from the HMS Tiger talks with Wilson in October 1966, Harper led opposition to the terms in the Cabinet, contributing to its ultimate rejection.

[47] Harper considered himself to have been overlooked when Smith gave the office of Deputy Prime Minister (which had been vacant since UDI) to the more moderate Wrathall the month before the Tiger conference.

The South African newspaper Die Beeld reported in December 1966 that the RF's right wing was poised to oust Smith in favour of Harper,[48] but this did not occur.

Wilson publicly welcomed his departure as a "step in the right direction",[51] prompting a retort from Smith that he did not appoint or sack ministers to please the British government.

In an attempt to co-ordinate opposition to the Rhodesian Front, the group made an election agreement with the Rhodesia Party (RP), which had been formed two years earlier; according to The Bulletin it was "seriously hampered by lack of established leadership" but nevertheless offered "the only real resistance [to the RF] in the polls".

"[56] He said that while he was not prepared to let black Rhodesians take control of the government, he understood that some form of power-sharing between the races was imperative to the country's future.

[56] The RF won all 50 white roll seats, denying the RP any representation in parliament; Harper himself lost decisively in the southern Salisbury constituency of Hatfield.

[60] In December 1975, two months after the disappearance of the prominent lawyer and black nationalist leader Edson Sithole from the middle of Salisbury, along with his secretary Miriam Mhlanga, Harper stepped forward claiming that the Rhodesian state had kidnapped them.

[61] In what became known as the "Harper Memorandum", the ex-minister alleged that Special Branch had interrogated Sithole at Goromonzi prison and then shuttled him between holding points around the country.

[62][63] Smith and non-militant nationalists agreed to what became the Internal Settlement in March 1978, and in January the following year whites backed the new majority rule constitution by 85% in a national referendum.