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All good things come to an end. For Roberto Martinez and Everton, that finale could come all too abruptly.

As the Toffees continue their assault on Champions League qualification, many - particularly those in north London - have questioned the morals of three key players being loaned in from top clubs.

Gareth Barry has been the lynchpin in allowing Martinez's free-flowing midfield, Gerard Deulofeu has shown off his exquisite talent in spells and Romelu Lukaku has spent all season proving to everyone that Chelsea do, in fact, have a top-class striker.

Deadly duo: Gareth Barry (left) and Romelu Lukaku have had a terrific season on loan at Everton The truth is that Everton have worked a flawed system flawlessly. It is an undesirable state of affairs that Lukaku can hurt Chelsea's rivals when not even based in west London.

Even better for Lukaku, who gets first-team football away from Stamford Bridge and the pressure of being second fiddle. Everton get a Champions League quality player.

But if Martinez's men do break into the top four, it is hard to see them carrying on that momentum shorn of those three players.

Back of the net: Lukaku wheels away having notches Everton's second goal in their 3-0 win over Arsenal last Sunday Christian Benteke's injury means Lukaku will be 100 per cent leading the line for Belgium at the World Cup.

If it's true that Jose Mourinho doesn't see him as part of his first-team plans for Chelsea, the World Cup will be the ultimate shop window, where Lukaku's value rockets to the kind of £30million fees a level above where Everton are able to play.

Everton with Lukaku Played 25 - Won 16 - Drawn 6 - Lost 3

Goals per game: 1.9

Win percentage: 64%

Points per game: 2.2 Everton without Lukaku Played 7 - Won 2 - Drawn 3 - Lost 2

Goals per game: 0.7

Win percentage: 29%

Points per game: 1.3 Advertisement

This would mean a major revamp of Everton's attack. The Toffees have won just 1.3 points per game without the Belgian as opposed to 2.2 with him in the side.

Naturally, the Toffees’ potency is also greatly reduced, with them relying on Steven Naismith or Kevin Mirallas for goals. With Lukaku, Everton manage 1.9 goals per game, and just 0.7 without him.

His 76 shots are the most of any Everton player, with him and Mirallas far and away the most forward-thinking Toffees. Losing this without replacement would be catastrophic.

Everton shots this season Lukaku 76

Mirallas 75

Barkley 68

Osman 45

Coleman 27 Advertisement

Lukaku may have grabbed all the headlines, but it is the capture from Manchester City who has made the team tick the most.

Gareth Barry has used the temporary switch to reinvigorate a career on its last legs to become one of the league's vital midfielders.

It's impossible to overstate what Barry gives the team. His steady and assured role allows players like James McCarthy and Ross Barkley to impose their style on the opposition.

Marksman: Lukaku has taken more shots than any other Everton player this season as he leads the attack

Everton with Barry Played 27 - Won 17 - Drawn 6 - Lost 4

Average Goals for: 1.7

Average Goals against: 0.9

Win percentage: 63%

Points per game: 2.1 Everton without Barry Played 5 - Won 1 - Drawn 3 - Lost 1

Average Goals for: 1

Average Goals against: 1.2

Win percentage: 20%Points per game: 1.2 Advertisement

Martinez has struggled by without his midfield lynchpin in just five Premier League games this season, with Everton winning only one.

They also concede over a goal a game without the former England man as opposed to 0.9 with him in the side.

He is central to everything Everton do.

Barry has the most touches on the ball in a game than any other player in the side, and his number of passes over a game comes in only behind Yaya Toure and David Silva, central stars for high-flying Manchester City.

Driving force: Barry plays a pivotal role in building Toffee attacks from his deep-lying midfield position

Touches per game: Everton Barry: 83.4

Baines: 82.8

Jagielka: 69.8

Coleman: 65.4McCarthy: 64.5 Passes per game: Premier League Yaya Toure: 70.7

David Silva: 70.5

Gareth Barry: 67.4

Michael Carrick: 66.9Aaron Ramsey: 66.9

His heat map in last weekend’s 3-0 destruction of Arsenal shows what he offers the team. He completely controlled the crucial area just inside Everton’s half, allowing the rest of the midfield to kill off the lacklustre Gunners .

Influence: Gareth Barry's heatmap against Arsenal demonstrates just how much influence he has for Everton

It’s no overstatement to say that Barry has been one of the best midfielders in the league this season. To replace what he gives Everton usually costs an absolute premium. Midfielders who can enjoy that level of control over possession in a Premier League game are a valuable commodity.

Good news then, that Barry seems the most likely out of any of the loan charges to pen a permanent deal at Goodison Park in the summer. Even so, his aging years mean he's still not a long-term solution.

Someone who would be is Gerard Deulofeu. One of the major talking points in England in the fallout of Barcelona's proposed transfer ban is that the playmaker will now stay with the Catalan giants.

While it was previously thought he may have been a slight level below what Barcelona need – not that that stops you being a superb player for 99 per cent of teams – they will now be looking to Deulofeu for fresh blood.

On target: Another loanee Gerard Deulofeu has also shown his class at times this season for Everton

Deulofeu has played only in fits and starts while he get to grips with the experience of playing in an honours-chasing side, and has also been overshadowed by the emergence of Ross Barkley, but his class has been clear. It’s another bright young talent that won’t be plying his trade at Goodison Park.

The problem with this route to the top is you generally only get to do it once. Manchester City, Chelsea and Barcelona might not be as open to lending top talent to a fellow Champions League club.

While Roberto Martinez has performed miracles this season, his greatest trick will come this summer when he has to Sellotape his side back together over the chasms that Lukaku and Barry will leave.

Do that and carry on from where they left off, and even Arsene Wenger won’t have anything to moan about.