Peter Lawwell, the Celtic chief executive, believes that if the Parkhead club ever found the door to English football open that they would have the potential to become the biggest club in Britain.

Celtic take on Manchester City tomorrow night in the conclusive game in Group C of the UEFA Champions League, with Brendan Rodgers’ side looking for what would be a relative giant-killing result in terms of the massive chasm in resources between the two teams.

Pep Guardiola, the Manchester City manager, spent more than £100m on transfers this summer, with riches available that Celtic can only look enviously towards. Lawwell, though, has maintained that if Celtic had the same television revenues available to them that they would rival any club in the English Premier League.

Read more: We will never give up pushing for a British league, says Peter Lawwell

“If we played in a football league like the English Premier League, I think we could be the biggest,” said Lawwell. “Because there is no barrier then; we have the whole bit so there would be no barrier to where we could go.

“We have the history, we have the story to tell, we have a global fanbase and we have the facilities. We have got the profile of a big European club but we don’t have domestic TV revenues. Our fundamentals are so strong.”

Celtic returned to the group stages of the UEFA Champions League for the first time in three years when Brendan Rodgers steered them into the elite tournament this summer, but Lawwell believes that in the intervening years that Celtic were on the outside looking it that the gap between the top level clubs has yawned even further.

Read more: We will never give up pushing for a British league, says Peter Lawwell

“I think the gap has widened,” he said. “To be fair we were in the most difficult group; we had an English team, a Spanish team and a German team this season. But did I feel that the quality had risen. We were up against three clubs from the biggest nations so it is extremely difficult. Perhaps in a different group, it might have been a different story. The group Leicester were in might have given us a better chance but overall I think we could consider that we have given a good account of ourselves. We have shown we can compete and this is only the first year. Brendan is just in the door here but we have shown that we can organise and we can compete and that can only get better.”