Boris Johnson has claimed it would cost more than £150 million and take at least nine months for Britain to hold referendums on Brexit and Scottish independence next year.
The Prime Minister said if Labour formed a pact with the SNP, Nicola Sturgeon would “demand” another “divisive referendum” on Scotland and a second vote on the UK’s EU membership.
Mr Johnson, who will launch the Conservatives’ Scottish manifesto on Tuesday morning, instead insisted his party would focus on delivering on the vote to leave the EU and the “people’s priorities”.
Tory analysis suggested that it would take a minimum of nine months to hold both referendums next year and would cost £155 million – with the second Brexit poll costing an estimated £138 million and the Scottish vote costing £17 million.
The party warned that giving the vote to 16-year-olds within nine months could cost up to £500 million or result in an additional delay of at least six months to pass the necessary legislation and allow the Electoral Commission to register them.
Labour leader Jeremy Corbyn has vowed to give voters the final say on Brexit in a second referendum – with a “credible” Leave option and Remain on the ballot paper – and has promised to resolve the issue within six months.
But he has said he would not support a second Scottish independence referendum within his first two years in office if he wins the keys to Number 10.
Ms Sturgeon said over the weekend that she would press for such a vote next year if she entered into an agreement to support a Labour government.
The PM said: “A majority Conservative government would get Brexit done and focus on the people’s priorities – such as increasing funding in our NHS and reducing the cost of living.
“The alternative is Jeremy Corbyn, a man who can’t even make up his mind on Brexit, submitting to a pact with Nicola Sturgeon, and we already know what terms she will demand – another divisive referendum on Scottish independence alongside a second vote on Brexit.
“The financial cost of this to taxpayers up and down the country will be in excess of £150 million.
“But the real cost will be much, much higher: the chaos of two referendums in 2020 grinding the country to a halt and the world’s greatest political union reduced to the status of a bargaining chip.”