By Alex Stevenson Follow @alex__stevenson
Senior Liberal Democrats are preparing the ground for a protracted struggle with "recalcitrant" peers over reform of the House of Lords.
Those reluctant for change in the upper House are preparing themselves for a bitter fight to keep the Lords an appointed chamber.
Given that the last parliament's MPs have already voted for both an 80% elected upper House and a 100% elected Lords, public opinion is likely to be on the side of the coalition government.
But Mr Heath warned Lib Dem activists, who have been pushing for reforms to be completed since the temporary measures of the Parliament Act 1911 exactly one century ago, that peers' "almost unlimited powers of delay" could pose a problem, however.
"We may have to go with the flow to a certain extent in terms of getting this legislation through," he told activists at a conference fringe event in Birmingham on Tuesday.
If both the Labour and the Conservatives agreed on an approach which the Lib Dems opposed it would be "silly" to put up a fight, Mr Heath said.
Other "extraordinary parliamentary mechanisms" might also be deployed against the Lords, three-quarters of whom are believed to oppose the measures.
The deputy Commons leader declined to elaborate on what those extraordinary mechanisms might be, although he did acknowledge these could include the Parliament Act.
Mr Heath added: "Have no doubts about it. We are serious about this reform and we want it to go through.
"It's going to be a test of nerve as much as anything else."
Lib Dem leader Nick Clegg unveiled the government's proposals for an 80% elected chamber in May.
They were dismissed by shadow justice secretary Sadiq Khan as a "dog's dinner", ending hopes of cross-party unity. Mr Clegg said at the time the government would be "pragmatic".
The draft bill is currently undergoing scrutiny from a parliamentary bills committee.