The Chamber returns Monday to the Fuel Stabilisation Reserve, the instrument drawn up by the Prime Minister's office and reinforced last week by Don Cordoba's public intervention. Forecourt prices hold at a three-year peak; the basin hostilities show no sign of easing. The sealed-reserve formula, by which drawings require a qualified majority and a declared emergency, remains the Government's preferred shape.

The Opposition continues to press for the seal to be broken and the reserve drawn upon without condition. Government whips expect the matter to carry on the Cordoba line, though by a narrower margin than last autumn's budget vote. Three independents from the coastal benches are understood to be undecided.

A senior official in the Finance Ministry, speaking on the usual terms, described the Monday sitting as "a test of the instrument, not of the coalition." The distinction is one the Prime Minister has laboured to maintain since March. Whether the Chamber accepts it will be clearer by Tuesday morning.

The tariff question (see Business, this page) now sits beside the reserve on the week's ledger. The Government has not yet indicated whether it will seek to address both in a single sitting or hold the trade matter for the Wednesday session.