[5] In 1951, Walls was promoted to the rank of Captain at the age of 24 years, and was appointed second-in-command of a reconnaissance unit that Rhodesia despatched to fight in the Malayan Emergency.
With the advent of global decolonisation, Southern Rhodesia came under increasing political pressure from the Colonial Office and the United Nations to introduce universal suffrage and majority rule.
During this period, Brigadier Sam Putterill, Walls' commanding officer, reproached him for permitting his men to wear paper party hats at a regimental Christmas dinner printed with the words, "RLI for UDI."
The new unit needed to combine cross-border insurgency warfare to take the fight to the enemies' bases of operation in territory under hostile governmental control (which collectively virtually encircled Rhodesia), with domestic policing counter-insurgency operations of a more traditional colonial nature, both disciplines being drawn heavily from the experiences that both Walls and Reid-Daly had learned when they had fought alongside one another in the Malayan Emergency twenty years earlier.
[11] In May 1977, General Walls received intelligence reports of a ZANLA force massing in the town of Mapai, in the neighbouring country of Mozambique, and he launched an attack across the border to remove the threat.
At this time Walls briefed the press that the Rhodesian forces were changing tactics from "contain and hold" to "search and destroy", and adopting a military policy of "hot pursuit when necessary."
In a candid admission to the press, Walls gave an insight to the nature of the conflict that Rhodesia found itself in when he stated in an interview in September 1978 that: "There is no single day of the year when we are not operating beyond our borders.
"[15] In 1977, rumours began circulating in the Rhodesian press that Walls had become deeply pessimistic about the future of Rhodesia, and that he had been quietly preparing to abandon the country and personally relocate his family into South Africa, and had covertly purchased property there for this purpose.
The Zimbabwe African People's Union leader Joshua Nkomo appeared on British domestic television laughing about this incident, declaring that Walls was responsible for the passengers' deaths because he was the "biggest military target", and this justified the action.
[18] With the nation increasingly pressured by sanctions, the Rhodesian government offered an amnesty to the nationalist guerrillas operating in the field in March 1979, printing and distributing 1.5 million leaflets entitled: "TO ALL ZIPRA FORCES".
The leaflets were printed with the signatures of Prime Minister Ian Smith, the ZANU founder Ndabaningi Sithole, United African National Council leader Abel Muzorewa, Chief Jeremiah Chirau, and Walls.
Following this in April 1979, Walls issued an order to the Selous Scouts Regiment to train, organise, and support militants who had defected to the Rhodesian government's authority as part of Operation Favour.
[19] This caused some surprise in military, political and diplomatic circles involved, and acrimony between himself and Rhodesia's last Prime Minister, Ian Smith (who had known Walls' father when they had served together in the Royal Air Force),[20] who privately accused him of betrayal[21] during the negotiations in London for the Lancaster House Agreement.
[22] In consequence of his newly found conciliatory demeanour, Walls was maintained as the Commanding Officer of the new Zimbabwe national army by the new Government to oversee the integration of the black nationalist guerrilla units into its regular armed forces.
Whilst the Western press and governments praised Mugabe's early announcements of his aim of reconciliation with the white community, tensions swiftly developed on the ground.
On 12 August 1980, the British Government issued a statement in response to the interview stating that Antony Duff, at that time the Deputy Governor of Salisbury, had replied to Walls in March 1980, notifying him that it would not interfere with the election.
[25] In response to the release of the interview with the BBC, the Zimbabwean Minister of Information, Nathan Shamuyarira, issued a statement that the new Government: "Would not be held ransom by racial misfits", and suggested that "all those Europeans who do not accept the new order should pack their bags."
At the turn of the century, as Zimbabwe became an economically chaotic state, the Government began to seize the properties and farmsteads of the remaining white farming population in an atmosphere of escalating menace and violence.
Paranoia also increased in the Government about perceived potential threats from the previous era to its rule becoming a focus for popular discontent; this was publicly displayed by articles appearing in state controlled press outlets[30] circulating rumours that Walls had covertly been crossing the border into Zimbabwe from South Africa to support the Movement for Democratic Change.
"[26] The Daily News later reported the Zimbabwean Government had confused Walls with Peter Wells, an English agronomist who had visited Harare to assist African farmers with water management.
Botha Airport) on the outskirts of George in the Western Cape, South Africa, whilst traveling with his wife for a holiday at the Kruger National Park.