EU referendum in UK: Susan Kramer and Mark Pritchard
17 September 2013 Last updated at 15:21 BST
Liberal Democrats are "slightly confused about their own position" over their commitment for an EU referendum, said Tory MP Mark Pritchard.
He called for clarity, and for his coalition colleagues to live up to their manifesto pledge on a vote, calling on them to support the Conservative Party position.
But Lib Dem peer, and former MP, Susan Kramer said her party had been clear a referendum should be around a proposed transfer of power and a constitutional change.
And she said the trigger for a vote should not be "just because the Conservative Party is afraid of the rise of UKIP".
The pair spoke to Andrew Neil and Jo Coburn on the Daily Politics ahead of Tuesday afternoon's Liberal Democrat conference debate on a motion about the EU,