In case you didn’t realise: the current Arsenal are not very good at defending.

Since the Laurent Koscielny-Per Mertesaker partnership was broken up in the 2016-17 campaign, the Gunners have gone from a side with a modest defensive record to one of the most diabolical backlines to grace the top-end of the Premier League.

Excluding the £35 million spent on Shkodran Mustafi – arguably one of worst pieces of business a Premier League club has ever done – the Gunners have forked out a measly £54 million on defenders since 2015. Half of that money was spent on William Saliba, who won’t arrive until 2020, and will need a few seasons to begin justifying that fee. In that time period, Arsenal have conceded 181 goals and never finished in the top four.

Their defensive woes have continued to cost the team points this season, most notably at Watford, making the case for an acquisition of a senior central defender all the more pressing.

The question remains, however, if Arsenal splash out on a top talent at the back, what would that senior defender be, given the current weaknesses of the side, the football Unai Emery wants to play at the Emirates, as well as the opposition Arsenal face week to week?

Age range

Given the likely high fee for such a player, Arsenal would want to be paying for an extended service, mostly in the player’s prime years.

Working on the rough estimate that a central defender’s prime age is between about 26-30, Arsenal would be looking for someone in the 24-27 range, with most of their development already completed, but a large chunk of their career still ahead of them.

However, the Gunners could compromise on this if there was a younger player with clear potential to be one of the best defenders

Non-negotiable skills

Most importantly, any senior defensive signing must not be error-prone. Arsenal have enough wildly fluctuating defenders on their books already and are in dire need of a calming presence at the back.

Arsenal have badly lacked an aerial presence for a while as well – they were one of the worst teams at generating xG from set-pieces last season, and they weren’t much better at defending them – so any expensive defensive acquisition would have to amend this deficiency at the back, lest Arsenal continually concede soft goals.

Finally, Arsenal’s dressing room is crying out for leadership. Granit Xhaka is a leader, but huge question marks remain over his place in the starting XI. Pierre-Emerick Aubameyang is 30, while Hector Bellerin, Rob Holding and Kieran Tierney are slightly too inexperienced to be the authoritative figure in the dressing room.

A central defender capable of defending calmly, on the ground or in the air, while organising the team and willing them to victory in the difficult moments of matches, shape as the foundational skills, is one Arsenal must look for in the summer.

‘Nice-to-have’ assets

Unai Emery places a huge amount of importance on the ball-playing ability of his central defenders – hence the continual selection of David Luiz despite many high-profile errors this season.

Any senior defensive signing would need to have at least some ability on the ball, particularly as Emery’s system of build-up does not give the central defenders many easy passing options into midfield.

Often, Arsenal require a risky or improbable pass from defence to allow the ball to transition between defence and midfield, and if this is to continue, then it’s probably better they buy a defender who can reliably make these passes.

A capable goal scorer would also be handy, as Arsenal rely far too heavily on their strikers for goals, and having a defensive player who scored 4-6 goals a season would allow the Gunners to get results on the rare days when neither Alexandre Lacazette or Pierre-Emerick Aubameyang are firing.

Finally, a defender adept with both feet would allow Unai Emery to be flexible with his other central defenders, with a truly two-footed centre back able to play on either the left or right side of defence, fitting in around their partners.

Does the above player even exist?

Laughably and appropriately, Arsenal are in need of a player with a ridiculously broad skillset, as shown above.

It may end up being impossible for Arsenal to get all of these skills in a single player. If there was a player who fitted into all those categories, they’d certainly be very, very expensive.

It’s also worth noting that the sheer number of attributes required in a single player in order to fix Arsenal’s defence shows just how far it’s fallen since the days of Lauren, Kolo Toure, Sol Campbell and Ashley Cole regularly shutting out the best attacks in Europe. The club clearly has a long way to go to return to the days of major success.

However, a peak-age, calm, commanding central defender who can dominate his own team, as well as the opposition, is the type of player Arsenal should be actively be hunting the market for, whatever the price they have to pay.

As Liverpool have shown with Virgil Van Dijk, the right signing at the right time can truly take a team from also-rans to the top end of Europe in a mere matter of months.