The tank was originally sited on Southsea Common in front of the Pier Hotel (Rees Hall).

The WW1 Presentation Tank

The tank probably had an inscribed plate attached to it, but this cannot be confirmed. The photograph on the left is inscribed with the words "Portsmouth's Tank - A Wartime Relic - Handing Over Ceremony - Christened by the Military "Annie Timpson" after the Mayoress."
Further Information
At the end of the Great War the army presented obsolete Mk IV tanks to many communities around the country that had played a conspicuous role in the war. Portsmouth received it's tank around 1920 and it was placed on Southsea Common, alongside Pier Road. The photograph on the left shows it at the Handing Over Ceremony.
The tank remained in place on the common until 1940 when it was sold for scrap. Before this happened however, gunners from the Royal Navy Gunnery School at HMS Excellent removed part of the engine in order to rebuild another tank that had been presented to HMS Excellent. The gunners actually succeeded in renovating their tank which then served in the Home Guard in Portsmouth during WW2. It was eventually taken to the Tank Museum at Bovington. Further details can be found on the HMS Excellent section of this site.
A third tank was presented to the town of Gosport, but nothing is known of it's subsequent fate.
Thanks to Michael Harrison from The Friends of the Lincoln Tank for alerting us to the former existence of this memorial and providing the photograph