'Roast' was a British special forces operation by commando units, supported by elements of the Special Boat Section, on and round Lake Comacchio in north-eastern Italy (1/2 April 1945).

Supervised by Lieutenant General C. F. Keightley’s V Corps, this was the first major element of the 'Buckland' spring offensive, which was the British counterpart to the US 'Craftsman', undertaken jointly to push Generaloberst Heinrich-Gottfried von Vietinghoff-Scheel’s Heeresgruppe 'C' back to and then across the Po river and thus to the north and entirely out of Italy. The breakthrough was to be made through the Argenta Gap, crossing the Senio and Santerno rivers, pushing forward to the Po river at Ferrara and releasing its armoured strength to swing to the north-west and race across country to meet the Lieutenant General Lucian K. Truscott’s US 5^th Army and complete the encirclement of the German forces defending Bologna.

On 1 April the whole of Brigadier R. Tod’s 2^nd Commando Brigade (Nos 2, 9, 40 [RM] and 43 [RM] Commandos) was engaged in 'Roast'.

Lake Comacchio was a very substantial body of shallow brackish water stretching from the Reno river in the south to a point above the town of Comacchio in the north and past Argenta in the west. This lake, or rather lagoon, is separated from the Adriatic Sea to its east by a narrow strip of land, or spit, no more than 1.6 miles (2.5 km) wide and cut by three canals linking the two bodies of water.

General Gerhard Graf von Schwerin-Krosigk’s LXXVI Panzerkorps of General Traugott Herr’s 10^th Army had a force of some 1,200 men of Generalleutnant Alfred-Hermann Reinhardt’s 98^th Division with which to hold this 'Spit', which the commandos were to clear, and thus secure the flank of Lieutenant General Sir Richard McCreery’s 8^th Army and suggest to the Germans that the notion that the main offensive would be delivered along the coast and not though the Argenta Gap.

No. 40 Commando undertook a feint attack to the south, crossing the Reno river, clearing and holding its northern bank, with the support of Arrigo Boldrini’s 28^th Garibaldi Brigade 'Mario Gordini' of the co-belligerent partisan movement, artillery and the armour of the North Irish Horse. No. 43 Commando was to attack up a tongue of land, to the extreme east, which constitutes the southern bank of the Reno river estuary, and when it had cleared this, cross the mouth of the Reno river and turn back to the south-west and clear the river’s northern bank, back toward one end of No. 40 Commando’s line. Nos 2 and 9 Commandos were to cross the lagoon from the south-west to points around the middle of the spit. No. 2 Commando was to land above the Bellocchio Canal and thereafter head to the south in order to capture the two bridges across it and thus prevent German reinforcements crossing. No. 9 Commando was to land to the south of the canal then head to the south along the lagoon’s shore and down the centre of the spit to clear all positions toward the new line held by No. 40 Commando.

The operation started on the evening of 1 April with the first engagement scheduled to start shortly after midnight. The lagoon crossing (marked in advance, though not very successfully, by Combined Operations Pilotage Party No. 2 and M Squadron of the Special Boat Service) took far longer than planned as a result of the lagoon’s very low water level and extremely muddy bottom. The commandos struggled through the muddy waters all night, manhandling their boats, and eventually reached the spit at first light, more than four hours behind schedule. Exhausted and covered in thick slime, they nonetheless pressed home their attacks.

Nos 2, 40 and 43 Commandos all reached their objectives relatively as expected, although Germans succeeded in blowing one bridge before it was captured by No. 2 Commando. No. 9 Commando initially progressed likewise until its Nos 5 and 6 Troops (especially the former) were strongly pinned down across a killing ground while attempting to capture the German-held 'Leviticus' position. Nos 1 and 2 Troops made good progress down the centre of the spit, and when advised of the situation of Nos 5 and 6 Troops, bypassed 'Leviticus' in order to turn about, lay smoke, and put in a bayonet charge from a position to the south-east of it. The position was overrun despite the fact that the smoke cleared more quickly than had been planned, exposing the commandos as they crossed the final 165 yards (150 m) to their target. Routed German defenders who fled to the north fell into the waiting Bren light machine guns of No. 6 Troop. No. 2 Commando captured 115 Germans during that day and No. 9 Commando another 232. No. 9 Commando’s casualties were nine killed and 39 wounded, of which eight dead and 27 wounded were of No. 5 Troop, more than half the commando’s strength. Even so, the ground gained was 7 miles (11.25 km).

During that evening, Nos 9 and 43 Commandos moved up to the bridges on the Bellocchio Canal held by No. 2 Commando. On the next day, 3 April, the Royal Engineers made serviceable the blown bridge, and the commandos moved over the canal, supported by tanks of the North Irish Horse. No. 2 Commando advanced to the north along the lagoon (western) side of the spit and No. 43 Commando along the Adriatic (eastern) side, No. 9 Commando being placed in reserve with a plan to execute an attack on Port Garibaldi after the next canal, the Valetta Canal, had been taken. The northern bank of the Valetta Canal was found to be very heavily defended, requiring a full attack which was later undertaken by Brigadier M. D. Erskine’s 24^th Guards Brigade of Major General J. Y. Whitfield’s 56^th Division.

The respective commandos cleared all positions up to the Valetta Canal, and the 2^nd Commando Brigade had succeeded in taking and clearing the entire spit and securing the eastern flank for the 8^th Army, in the process taking 946 prisoners, 20 pieces of artillery and a number of mortars and rocket-launchers.

It was later established that in 'Roast' the Germans had effectively lost three infantry battalions, two troops of artillery and a company of machine gunners.