Voting should be compulsory for young people taking part in a general election for the first time, according to a report published on Monday by the Institute for Public Policy Research.
With Labour committed to lowering the voting age from 18 to 16, the thinktank said compulsory first-time voting was necessary to ensure that the wide gap in turnout between young and old did not get worse. First-time voters would face a small fine if they refused to participate in an election. They would have the option of voting for "none of the above".
Guy Lodge, one of the authors of the report, said: "Unequal turnout matters because it gives older and more affluent voters disproportionate influence at the ballot box. Turnout rates among the young have fallen significantly which means there is less incentive for politicians to pay attention to them."
In 2010, there was a 32-point turnout gap between 18- to 24-year-olds (44% of whom voted) and over-65s (76% of whom voted). In 1970, that turnout gap was just 18 points.
Cutting the voting age to 16 without introducing compulsion could make this worse, the report says.
According to the IPPR, about a quarter of democracies use some form of compulsory voting.
Sarah Birch, a co-author, said: "First-time compulsory voting could well be very effective in engaging young people in politics. There are many other things that young people are required to do, not the least of which is go to school.
"Adding just one more small task to this list would not represent an undue burden, and it could well help to reinvigorate democracy."
Extracts from the report, Divided Democracy: Political Inequality in the UK, were due to be released on Monday, but the full document will not be published until September.