 In the second phase of the operation , the 17th Infantry Brigade exploited the breach made in the perimeter , and pressed south as far as a secondary line of defences known as the Switch Line . On the second day , the 16th Infantry Brigade captured the township of Bardia , cutting the fortress in two . Thousands of prisoners were taken , and the Italian garrison now held out only in the northern and southernmost parts of the fortress . On the third day , the 19th Infantry Brigade advanced south from Bardia , supported by artillery and the Matilda tanks , now reduced in number to just six . Its advance allowed the 17th Infantry Brigade to make progress as well , and the two brigades reduced the southern sector of the fortress . Meanwhile , the Italian garrisons in the north surrendered to the 16th Infantry Brigade and the Support Group of the British 7th Armoured Division outside the fortress . In all , some 36 @,@ 000 Italian prisoners were taken . 
