LONDON — Britain’s government has announced that starting in August, businesses must start sharing the costs of a job retention program that has effectively placed workers furloughed amid the coronavirus pandemic on the government payroll.

The unprecedented program has so far covered the wages of some 8.5 million people and has cost 15 billion pounds ($18.4 billion). It has covered 80% of wages up to 2,500 pounds per worker each month.

Treasury chief Rishi Sunak said from July, businesses can decide to bring furloughed workers back part-time if they want. In September and October, employers will need to contribute 10% and 20% of furloughed wages respectively.

Sunak also announced he is extending a support program for self-employed workers. From August, those eligible can claim an extra grant capped at 6,570 pounds each. The program has so far seen 2.3 million claims worth 6.8 billion pounds.