Hartley has enjoyed a stellar start to Test cricket, leading the wicket-taking charts in India with 20 dismissals. That haul began with a match-winning 7 for 62 on debut in Hyderabad for what has been the tourists' only victory in four matches.

With the series lost, the final Test in Dharamsala is a chance for England to add gloss to a scoreline that currently reads 3-1 against. Even if Hartley does not add to his tally, he will likely finish as the team's player of the series.

Lancashire's acquisition of Lyon, who has 527 Test dismissals, is a shrewd bit of business. At the time of the signing, Hartley's modest average of 36.57 from just 20 first-class matches hinted at the need for a more accomplished spinner. Now, after a remarkable six weeks, Hartley is an altogether different proposition.

"Obviously signing another spinner, you think about it a little bit," Hartley said. "The type of bowler he is is something I'm trying to work on.

"He's someone I want to try to replicate. Over here I've tried to replicate [Ravindra] Jadeja and Axar [Patel]. To be an international cricketer you have to able to perform in different conditions and I think Nathan is the next guy that can really help me. I'm really looking forward to it.

"The way he operates in Australia on pretty flat wickets, there are times when English wickets are similar. He's going to be great to learn off."

One area Hartley has already identified to work on with Lyon is varying his seam presentation. Hartley's "natural shape" on the ball comes through an action that has the seam rotating close to the horizontal plane - otherwise known as "barrel spin". While that has worked for him in India - left-arm spinner Axar is a fellow barrel spinner - he acknowledges success elsewhere, including England, requires a more up-and-over approach.

"Nathan bowls a bit more over the top. In flatter conditions, you want a bit more over the top just so you get that real drop and bounce and probably a bit more spin which is better suited to English conditions. Naturally, I'm more of a barrel spinner, so I'll just try to get tips off him [Lyon] and bits about his preparation.

"If you watch Bashir, he's quite a natural over-the-top bowler and that's what comes natural to him. I'm sure it's probably not as hard as I think it is but that's just what comes out naturally for me - I'm sure with a bit of practice, I'd be able to get a bit more consistent and a bit more over the top."

Hartley enjoying six-hitting exploits

Hartley's 159 runs in India have shown there is plenty to work with. Prior to his seven-for in the first Test, his 34 in the second innings came in a vital 80-run stand with centurion Ollie Pope that eventually saw India fall 28 short of a 231-run target. Cultivating that extra string could solve both his and Lancashire's conundrum, and even allow Hartley to steal a march on Jack Leach for this summer's Tests against West Indies and Sri Lanka.

"It's hard to play a spinner early in the season so I'm really trying to work on my batting and become more of that allrounder role which makes me a lot easier to pick. Obviously, I've not got to neglect my bowling.

"I've made big strides in these last two years with my batting but I still feel there are gaps there, and that [improving] only really comes with time at the crease. You don't want to put too much pressure on the rest of the team by batting too high. It would be nice to bat seven or eight."

Hartley admitted the "gaps" in his batting are primarily down to impulse. "I think I get a bit carried away trying to hit sixes and fours. I think sometimes I've just got to relax myself and just take my time to get in and just have a bit more patience, really."

But it is that propensity to hit big shots that has him as a favourite in this set-up. No England player has struck more than his six sixes, something McCullum and his captain Ben Stokes have thoroughly enjoyed.

"They're over the moon whenever I hit a six. That's what I get cheered for. Coming back in the dressing room, that's what they talk to me about: 'That was a nice stroke.' And I'm like 'yeah, it was.' It just encourages me to play more of them to be honest. I'd rather get out like that than defending really.

"It's a lot different to when I get hit for six," he said of different reactions to the ball sailing over the fence from his bat rather than off his bowling. "It's fantastic. These crowds have been amazing but there's nothing better than shutting them up because they are very loud."

R Ashwin has been on the receiving end of four of those hits. Only Travis Head (in 2023) and Steve Smith (2014-15) have struck the offspinner for five in a single series. Could Hartley reach or even better that mark in what will be Ashwin's 100th Test cap? He certainly hopes so.

"Because these guys are so accurate, there's not much room and the way they set their fields it's hard to really work them and work them around," Hartley said. "It's not really a massive skill of mine.

"It's really nice hitting people for six as well. On these wickets that are doing a bit and keeping low, you might as well score them while you can until you get a good one. Hopefully I can hit him for a few more in these last two [innings] - or anyone really."