A poll released this week showed Sen. Susan Collins (R) with a double-digit lead over Rep. Tom Allen (D), who is stepping down from the House to challenge the Senator in her bid for a third term.

Collins led Allen, 56 percent to 31 percent, with 13 percent undecided, according to the poll. The Pan Atlantic SMS Group Omnibus poll surveyed 400 likely voters June 10-18 and had a margin of error of 4.9 points.

Many publicly released polls over the past year have showed Collins with a double-digit lead over Allen, which has raised questions about whether the Democrat could close the gap.

However, Allen spokeswoman Carol Andrews pointed to other polling, including internal surveys, that show movement in the race.

“We have always known Susan Collins’ name recognition surpasses that of Congressman Allen by many points, and that is certainly bankable for horse-race margins,” Andrews said. “That dynamic will change drastically and quickly once the paid advertising campaign meets the grass-roots campaign.”

Collins campaign spokesman Kevin Kelley said the Republican’s camp was “encouraged” by the numbers.

“Sen. Collins has always made it a priority to work across the aisle, to seek consensus and to get the job done,” Kelley said. “It’s clear that Mainers appreciate her hard work, and we are pleased to have the overwhelming support of Republicans, Democrats and Independents.”