'DF' (i) was a British operation to destroy as much as possible of the Belgian port of Zeebrugge, and to block maritime access to this port, before the arrival of the German forces (26/27 May 1940).

The ships were originally have been used to block the port of Ostend in the same country, and the entire force comprised the destroyer Vega, the sloops Mallard, Shearwater and Sheldrake, and the motor torpedo boats MTB-14 and MTB-15, which were most of the original force, less the minesweepers, destined for the attack on Ostend, and the blockships were the 1,943-ton Atlantic Guide and 2,004-ton Borodino.

The two blockships were scuttled successfully in the channel, and their skeleton crews were recovered by the motor torpedo boats.