The offensive started on early 18 November 1941 with the 30th Corps rolling across the frontier with Libya. With no opposition, they easily reached their initial objectives by evening. That did not prevent them from losing tanks to mechanical breakdowns. This is the status by the end of 18 November:
Unit Tanks at start Runners by end of 18 November
7th Armoured Brigade 141 119
22nd Armoured Brigade 155 136
4th Armoured Brigade 165 not known but few breakdowns
The Stuarts were much more mechanically reliable than the British tanks, so the 4th Armoured Brigade finished 18 November a nearly full strength, although we do not know the exact number of runners.
On 18th November, the 13th Corps just moved up close to the enemy forces. The weather had continued to be poor, but had the advantage that German and Italian aircraft were kept on the ground. However, British air reconnaissance was also affected, due to low visibility. That left General Cunningham wondering what to do next, as the initial movements had not provoked a response. This is based on the account in Vol.III of the Official History.