He was born in Rhodesia in 1927 into family with military tradition. His father, George, had been a pioneer pilot in the colony and had volunteered for service with the Royal Air Force shortly after its formation. When Peter left Plumtree School, one of the most distinguished in Rhodesia, he already had his sights set on an army career. He volunteered for the British Army during WW2 and attended the Staff College at Camberley, which welcomed students from the Commonwealth. When the war ended he joined the Black Watch and was appointed Assistant Adjutant in the Highland Brigade Training Centre. He resigned his commission when the Army decided to transfer him, choosing, in his own words, "to return to my beloved Rhodesia rather serve in any regiment other than the Black Watch". He could not stay away from soldiering for long, joining the Southern Rhodesian Staff Corps in the rank of corporal. With his experience and application he was promoted rapidly through the ranks and was soon commissioned again.

He went to Malaya during the military operations against the communist insurgency from 1951 to 1953 as commander of "The Far Eastern Volunteer Group" (which became "C" Squadron (Rhodesia) 22 SAS). It was composed entirely of Rhodesian officers and men, who were physically tough, well educated and idealistic. Despite a tendency to suffer more from tropical diseases than other Commonwealth troops, they proved themselves to be outstanding jungle fighters. On return home, their unit continued on as C Squadron, SAS right up to their disbandment in 1979. 22 SAS honoured their Malayan service, by leaving their squadron slot vacant to the present day. Walls was made a MBE (military) in 1953 for his Malayan SAS service where he also wrote himself into airborne history.

n May 1952, Major Walls took part in a parachuting experiment to ascertain the theory of ‘Tree-Jumping’, which went against all orthodoxy. From a RAF Dakota over the Betong Gap, along with Johnny Cooper (a WW2 SAS ‘Original’), he was to deliberately steer his X-Type parachute into the rain forest canopy and hopefully snag it in the 200 foot high trees. He would then abseil down using a 150 foot long knotted rope. It seemed reckless but there was method to the madness. Three months before, high wind caused an entire SAS stick to be dropped in trees, with only light casualties.

I The men had climbed safely down using ropes. That got the SAS ‘head-sheds’ thinking. It may be safer to snag chutes in the forest canopy, than risk landing blind onto a cleared DZ, containing lethal hazards such as razor sharp bamboo and deadwood logs. All that was needed was a more efficient way of getting down. Walls was encouraged to do the first test jump. He landed safely in the trees, but unfortunately a minute before, a trailing static-line from his chute broke Coopers arm on exiting. Cooper was safely retrieved without further injury from the trees. Tree-jumping continued to be used by the SAS till 1954, before, inevitably, being abandoned due to an increase in injuries from the trees.

Walls continued to shine, and in 1964 assumed command of the 1st Battalion, the Rhodesian Light Infantry (RLI), an unit of tough young professional soldiers which was to become famous in the bush war. He was the ideal commander for "troopies", as the soldiers of the RLI were known. Walls was tall, broad-shouldered and a man of action who liked to lead from the front. He was also a convivial and personable man who surprised those who served under him with an amazing memory of names and family circumstances.

In 1972 Prime Minister Ian Smith approved the appointment of Walls as General Officer Commanding the Rhodesian Army, as the bush war began in earnest. He knew from his Malayan experience that a key element in any anti-guerrilla war strategy would be the gathering of intelligence from within the enemy ranks. He summoned his old friend and colleague from the Malayan emergency and the RLI, Ron Reid-Daly, and asked him to form the Selous Scouts, a unit that ostensibly would be for tracking but would operate clandestinely behind and within guerrilla ranks.

He also realised that the small white minority population of Rhodesia would never be able to hold out against the larger guerilla forces aligned against them, if they chose only to react, against enemy attack. Thus, he advocated a policy of pre-emptive action against guerilla bases in neighbouring African countries. 20,000 guerillas were killed in the course of the war by units such as the RLI, SAS, Selous Scouts and Rhodesian African Rifles. Walls, now Commander of Combined Operations, said in September 1978 that there is "no single day of the year when we are not operating beyond our border”. Unfortunately, it was always lack of international recognition (plus crippling UN sanctions) for Rhodesia that undermined any military success. Eventually, a 1980 peace deal negotiated at Lancaster House, Salisbury resulted in a British interregnum in Rhodesia, with Lord Soames as governor backed by a team of top Foreign Office officials and a small force of British troops. Walls, as army commander, found himself drawn inexorably into the political process.

Following Robert Mugabes unexpected landslide victory, Walls immediately wrote to Magaret Thatcher calling for a new election, claiming that the imperfect "assembly point" plan for guerrillas to gather and hand in their weapons had not worked and that the insurgents had infiltrated most rural areas. His plea was in vain. The beleaguered general decided that the best option was to opt immediately to serve the Mugabe regime by organising the amalgamation of the rival armies, believing this would offer the best future for the many thousands of professional officers and men who had fought for him for so long and with much sacrifice.

Mugabe, in the spirit of reconciliation he affected at the time, agreed. Walls went on national television to warn that troublemakers among his former forces "will not be tolerated". It was too late. On 17 March 1980, after several unsuccessful assassination attempts Mugabe accused Walls of involvement, "Why are your men trying to kill me?" which Walls refuted with the most obvious retort, "If they were my men you would be dead”. After relations with Mugabe further declined, he exiled himself to South Africa where he stayed till his death in 2010.

May he rest in peace