LONDON -- Britain's governing Conservative Party was striving Monday to defend an election platform that is light on policy proposals, as it tries to avoid squandering its poll lead before the vote in less than three weeks.

Prime Minister Boris Johnson's party is campaigning heavily on a promise to "get Brexit done" by taking Britain out of the European Union on the scheduled date of Jan. 31, if it wins the election.

Despite the definitive-sounding slogan, Culture Secretary Nicky Morgan conceded that leaving the bloc would only be "the first big step" to completing Brexit, because it would be followed by negotiations on a new trade relationship with the bloc.

Johnson pushed for Britain to hold the Dec. 12 election, which is taking place more than two years early, in hopes of winning a majority and breaking Britain's political impasse over Brexit. All 650 seats in the House of Commons are up for grabs.

The Conservatives lead the main opposition Labour Party in opinion polls, and the party is taking a cautious approach in the remaining 17 days of the campaign.

On Sunday the Conservatives published an election manifesto -- the bedrock of British parties' election campaigns -- that is light on plans for the country beyond Brexit.

It includes voter-friendly promises to fill potholes and scrap some hospital parking charges, and commits to a modest increase in public spending, though far less than that proposed by the main opposition Labour Party. Labour, under left-wing leader Jeremy Corbyn, has set out plans for a radical expansion of public spending and state ownership if it wins the election.

Notably, the Conservative manifesto does not include a proposal for how to fund the increasing cost of social care for the elderly and others who need it, despite Johnson's earlier promises that the Conservatives would grapple with the difficult issue.

Many Conservatives believe a botched social-care proposal in the party's 2017 election platform -- dubbed a "dementia tax" by opponents -- cost the party its majority in Parliament, and led to more than two years of political deadlock over the terms of the country's departure from the EU.

Paul Johnson of economic think-tank the Institute for Fiscal Studies said the Conservative promises would be considered modest if they were put forward in an annual budget.

"As a blueprint for five years in government, the lack of significant policy action is remarkable," he said.