Officials are in desperate talks to secure five million doses of vaccines from India, amid growing tensions over the Prime Minister’s planned trip. Boris Johnson is due to fly to India next weekend in a diplomatic visit which has already been scaled back as cases of Covid across the country continue to surge. In recent days there have been growing calls on Mr Johnson to cancel the trip, with scientists saying the decision to keep India off the quarantine “red list” is “mystifying”. Government sources said that amid the diplomatic negotiations, talks are still ongoing about when Britain will receive a long-overdue order of vaccines from India. The UK ordered 10 million doses of AstraZeneca from India’s Serum Institute, which were due to arrive last month. But so far Britain has only received half the delivery, after the Indian government stepped in to prioritise doses for domestic use, as cases soared. The delays set back the rollout of the NHS vaccination programme, vastly reducing the number of first doses being administered this month. Several states in India are now reporting shortages of jabs, with their leaders urging the government to meet domestic demand, sparking fears exports could be blocked. Yesterday one UK government source said: “We are still expecting to get the other five million doses, it is just a matter of when. We don’t have a confirmed date.” A second source said: “They are still negotiating the details, but we are expecting the deal to be done”. On Friday No 10 signalled that Mr Johnson is reluctant to push back what will be his first major international trip since securing a post-Brexit trade deal with the European Union. Late last month, his envoy, Lord Eddie Lister, travelled to India to visit the Serum Institute, as part of efforts to secure the vaccine doses, ahead of Mr Johnson’s visit. In the last week, new cases in India have reached more than 260,000 a day, while 77 cases of the Indian variant of Covid have now been reported in the UK. Scientists are concerned that the soaring cases across India suggests the variant may be more transmissible, with fears it could evade vaccines. Dr Susan Hopkins, chief medical adviser to NHS Test and Trace, on Sunday said some cases found in the UK have no clear link to travel from India. Health officials from the UK are now talking to colleagues in India to attempt to secure samples from them, in order to carry out lab studies into the variant. On Friday Professor Adam Finn, of the Government’s Joint Committee on Vaccination and Immunisation, said he found it "mystifying" and "slightly confounding" that India is not on the Government's "red list" for travel.