(Bloomberg) — Boris Johnson is under pressure to announce a ban on telecoms companies from installing new equipment made by Huawei Technologies Co in Britain’s fifth-generation mobile networks from as soon as the end of 2021.

Britain’s National Security Council meets Tuesday to decide on the company’s future in the U.K. in the wake of U.S. sanctions against the company. According to people familiar with the matter, a review concluded that Huawei will now have to use untrusted microchips, making 5G security risks impossible for the U.K. government to control. Culture Secretary Oliver Dowden could announce the decision straight afterward.

Members of Parliament in Johnson’s own Conservative Party have been determined to force the government to reverse its January decision to allow the company to supply 5G equipment. Confident that they’ve won that argument, they now want specific commitments on timing.

“The sanctions have changed the dynamic,” said Bob Seely, one of the leading Conservative rebels. “The government is listening, and it’s important to give them credit for trying to do the right thing.”

Two Dates

Seely said MPs wanted two things from the government: A “no new kit date,” after which no one would be able to install Huawei equipment, and a “rip out date,” by which time the company’s technology would have to be completely removed. He said he favored a no new kit date in late 2021, and he said the debate among his colleagues for the rip-out date was between 2023 and 2025.

Other potential Tory rebels didn’t go so far. Neil O’Brien said he was “open-minded” on timing, and said he was less worried about forcing the removal of older equipment “which will come to the end of its life over a couple of years.” Damian Green also said he was “less concerned” about older equipment, and said he simply wanted a new equipment ban “in this parliament” — by 2024.

A crackdown on Huawei would further escalate tensions between London and Beijing, already under strain over Hong Kong and the handling of the coronavirus pandemic. But the level of opposition in parliament leaves Johnson with little choice.

Conservative MPs fired a warning shot in a symbolic vote in early March. The escalating diplomatic row over Hong Kong is only likely to have increased their fears about allowing a company with close ties to the Chinese state to supply equipment for critical infrastructure.