‘The burn was extreme’: re-creating Penny Mordaunt’s sword-wielding feat

Until this week, Penny Mordaunt’s only public display of athleticism was a high-dive belly flop on the ITV gameshow Splash! But the Tory minister became the surprise star of the coronation after she carried the enormous sword of state for a whopping 51 minutes without breaking sweat.

In the interests of science, the Guardian wanted to find out just how much of an endurance feat Mordaunt’s performance was.

The ceremonial sword is the heaviest in the royal collection and weighs 8lbs (3.6kg) in its gold-encrusted sheath.

Attempting to re-create the scene, I scoured the house for a suitable test object. Our only sword is an 85-gramme foam one my daughter picked up in Legoland, so instead I opted for an oversized plastic jug bought for a kid’s birthday party. A resplendent gold sword it is not, but full up, it would reach the right weight.

Related: On point: Penny Mordaunt seizes the moment at coronation

When I struggled to lift the full jug out from under the tap, I realised this was going to be harder than I thought.

Mordaunt said she had been “doing some press-ups” and training with a weighted replica as preparation for carrying the sword. My few hours of preparation were a little less rigorous and largely involved sitting at a laptop lifting cups of coffee.

My one hope for vestigial arm strength was having a three-year-old who still doesn’t like walking. Surely carting around a recalcitrant preschooler was harder than standing still with a spangly sword?

Less than 30 seconds in, it became clear how wrong I was. My arm tremors were already rippling the surface of the jug, making it look like the cups in Jurassic Park when the T rex was incoming.

The burn was extreme. I tried tucking my arms against my hips to bear the weight, but that did not work for long, and I did not see Penny doing that.

As time went on and the arm wobbles increased, I used language that would not be becoming in Westminster Abbey. After seven minutes, the water was beginning to slosh over the side as my arms became uncontrollable.

How did Mordaunt look so serene? There was no sign of a tremor or bead of sweat as she strode through the abbey in her specially commissioned power dress and cape, holding the sword at a perfect right angle.

At 8 minutes and 42 seconds in, as the arm judders reached their peak, I succumbed to the inevitable and let go of my jug of state, soaking my feet in the process. The jug did not survive the experiment, making me grateful it was not a priceless artefact handmade for Charles II.

Mordaunt was given the role of lord president of the privy council as a demotion by Liz Truss after losing out in the leadership race, but in less than an hour of sword-wielding, she has used it to pull off a PR coup.

Even the former Labour spin doctor Alastair Campbell was gushing, saying: “Don’t let anyone ever say I never say anything positive about Tories … I am in awe of Penny Mordaunt’s arm and shoulder strength!”

At not quite 40, I’m 10 years Mordaunt’s junior, but I’m not sure my guns will ever give hers a run for their money. In the words of Labour MP Chris Bryant: “The Penny is mightier than the sword.”