A ferocious storm expected to hit Britain tomorrow night could bring coastal flooding along the length of the country as well as winds of up to 80mph, forecasters said.

A band of exceptionally low pressure — close to the record pressure depth recorded in Perthshire in 1884 — is expected to hit the West Coast of Ireland on Sunday, bringing heavy rain and severe gales across Britain. The unsettled weather is expected to climax on Monday morning when the deepening low-pressure system swings east across the country. Severe weather warnings have been issued by the Met Office for much of Britain.

People are being warned to stay inside tomorrow night and avoid unnecessary journeys.

However, the conditions will be greeted more warmly by some inhabitants — with toads likely to benefit from the rainfall. The past few weeks have been so dry that most of the nation’s toads, recently roused from hibernation, have been unable to make their annual pilgrimage to their mating ponds.

The storm, the strongest of the winter, also brings the risk of disruption to transport and power supply networks, with winds strong enough to uproot trees and damage buildings, according to forecasters. But at this stage they are not predicting the storm will be as severe as the devastating storm of October 1987.

Pressure in the centre of the low could fall as low as 935mb west of Ireland. The lowest pressure yet recorded over the UK was 925.6mb at Ochtertyre, near Stirling in 1884. However, the storm forecast for Monday was unlikely to be quite that deep when it crossed the country. The deep depression is brewing at present in the Atlantic. It will explode into a “bomb” — an extremely powerful storm that intensifies so rapidly it loses around 1 millibar each hour for 24 hours.

By the time storm hits the UK the intensity will have eased off slightly, giving winds gusting to 70mph inland, although the Met Office gives warning of the risk of disruption to transport and power supplies, as well as heavy downpours of rain. Nowhere in the country will escape the onslaught as the area of the storm is truly colossal, covering about half the North Atlantic. However, its sheer size is a saving grace, because smaller intense storms funnel even stronger winds along steeper gradients of pressure, which is what happened in the notorious October 1987 storm.

Brian Golding, head of forecasting at the Met Office, said: “The arrival of this exceptionally deep area of low pressure is expected to coincide with spring tides on Monday bringing the risk of flooding to western coasts stretching from southern England to northern Scotland.”