There are indications that the South African military build-up in Rhodesia continued after the Patriotic Front's conditional acceptance of the ceasefire on 5 December and the arrival of Lord Soames on 12 December. On 7 December, for example, the Times correspondent reported seeing a long convoy of South African army vehicles and troops moving in a northerly direction along the Beit Bridge to Fort Victoria road. The troops were all white and numbered about 60 men. Some of them were seen well to the north of Rutenga, travelling even further into Rhodesia. On 15 December, 50 South African army trucks were reported to have arrived in Salisbury and to have been seen unloading military equipment at the railway station. Following agreement on the ceasefire, the Patriotic Front lodged repeated protests with the British Governor at South Africa's continued presence, alleging that South African troops wearing Rhodesian uniforms were being brought into the country to reinforce Rhodesian security force units. In an interview published in the Mozambique newspaper Noticias on 6 January, for example, the President of ZANU (PF), Robert Mugabe, said that SA troops were still arriving in Rhodesia "in their hundreds". ZANLA field commanders had reported the arrival of 20 truckloads of SA troops within the past few days.
No British newspaper had reported seeing any South African troops leaving Rhodesia, by the time FOCUS went to press. On 7 January, however, British officials in Salisbury were reported to have confirmed the withdrawal of an estimated 1,000 South African troops. A spokesman said that all the units had left the country with the exception of "a small force of South African regulars guarding the Beit Bridge border crossing over the Limpopo river", whose presence had been authorised by the Governor. This concession had followed "long and difficult negotiations with the South African government", the spokesman said. On 8 January, the British government was informed by the Southern Africa Committee of Commonwealth High Commissioners in London that the decision to authorise the continuing presence of SA troops in Rhodesia was a violation of the Lancaster House agreement. In Maputo, President Samora Machel of Mozambique told the diplomatic corps that SA forces were continuing to "flow into Zimbabwe with the declared intention of thwarting the democratic electoral process", and that this was "an abusive violation of the London accords".
The British authorities, in an apparent reversal of earlier statements in which the SA troop presence at Beit Bridge had been described as the "single exception" to Lancaster House, subsequently denied that there had been any contravention of the agreement. Lord Soames's press spokesman, Mr. Nicholas Fenn, stated at a press briefing on 14 January that there were "no South African troops under-South African leadership inside Rhodesia other than the small contingent guarding Beit Bridge; their presence did not violate the Lancaster House agreement, nor did it represent intervention; and the force would not be used elsewhere in the country". He agreed that "there were South African troops in the Rhodesian security forces as there are other nationalities", but "none was under South African leadership". Mr. Fenn also said that "it would be preposterous to suggest that it (the South African force) would have influence over voters. Its future is for the independence government to decide".
British officials maintained by this time that the South African presence comprised 150 troops on the Rhodesian side of the border at Beit Bridge, with a further 250 in the immediate vicinity on the South African side. Other "sources" referred to 250 SA troops deployed within a 7 mile radius of Beit Bridge and equipped with artillery.
The President of ZANU (PF), Mr. Robert Mugabe, however, stated that there were now 6,000 SA troops in Rhodesia, half of whom had arrived since September 1979. ZANU's "Voice of Zimbabwe" radio programme from Maputo said that SA had 3,000 troops stationed in the Beit Bridge area, ready with trucks and equipment for an armed intervention. This troop presence seemed to be increasing day by day, the radio said, and transit facilities for the troops had been set up in a sealed-off area of Beit Bridge railway station. The "Revolutionary Voice of Zimbabwe" Patriotic Front programme from Addis Ababa stated that there were "three to four battalions" of SA troops "all over Zimbabwe".
