With only three games left to play, this season should be one to remember at Tendring Volleyball Club.

For the first time in their 28-year history, the unbeaten men’s side are on the cusp of promotion to the national super league. But instead the Essex team’s euphoria has been replaced by dismay. If Tendring do go up, they, like many other amateur sports sides right now, will have to do so without some star players.

New Home Office visa regulations have led to foreign students being advised that they can no longer compete in amateur sport events beyond those organised by their university.

“It’s not a good mood at the club,” said Bastien Chabe-Ferret, an economist at the University of Essex who coaches at Tendring. “We feel very sorry for the students; it’s really sad. We’re unbeaten in the season and now we’re left to finish the work to make it to the top division without some of our best players.”

Volleyball has been particularly hard hit. It is estimated that about a third of the players in the top league are from overseas. Five Tendring student players – four Americans and one Canadian – withdrew from the side after receiving advice from their university’s immigration officer.

“Half of our starting line-up cannot play any more,” said Chabe-Ferret. “Strong teams like Durham are struggling and others are having to cancel games because they cannot gather a team from one week to another.”

Ice hockey, basketball and women’s football are also said to be reporting problems. Questions hang over what it could mean for students who have played cricket at a relatively high level back home and now want to join a local club this summer.

The Tier 4 visa regulations, which apply to students from outside the EU, were introduced in January and provide a broad definition of who is considered a professional sportsperson. This can include anyone who has received payment in kind in the past four years for playing sport; has been registered with a professional or semi-professional team, including academy development team age groups; has represented their national team, including at youth level; their state or regional teams, including at youth level; or has an established international reputation.

For amateur sides that rely heavily on students from North America, many of whom have earned sports scholarships back home, this has proved disastrous. “To make matters more confusing, the definition of a professional is not about being paid; even having an aspiration to play at a professional level means you could fall foul of the rules,” said Alex Porter, Tendring Volleyball Club chairman.

Having taken legal advice, British Universities and Colleges Sport (BUCS) sent a confidential briefing to its member universities explaining that the regulations prevented the nearly 224,000 students who entered the UK last year on a Tier 4 visa from any “form of coaching role for local sports teams or clubs”. It also stipulated that “students are not able to compete in events outside of BUCS, ie in regional, national or international leagues”.

Porter said universities could not be expected to know which sports had a professional element and which were purely amateur, or which of their students had been paid to play, meaning they had been advised to tread cautiously. “Universities must protect their visa licences and ensure their students don’t breach their restrictions. They aren’t experts on the status of each sport’s professionalism, the structure of each sport, or indeed on the sporting history of each Tier 4 visa applicant. All the university knows is that a student is from outside the EEA and they want to study in the UK. As a result, and based on the information provided by the Home Office and BUCS, they had to issue a blanket ban on Tier 4 students playing outside of BUCS.”

“We just can’t risk it,” said Barry Squires, business and partnerships manager at the University of Bournemouth. “The decision from our immigration adviser, who has a direct link in to the UK visa authority, is that Tier 4 students can’t play.”

A Home Office spokesman said: “It is incorrect to suggest students on a Tier 4 visa cannot play amateur sport.” Privately, however, the department acknowledges the problem. It has met with the Sport and Recreation Alliance, which represents local sports clubs, and will meet with BUCS on Thursday. “We want to ensure that international students have, where possible, the same opportunities as UK students to play, coach and officiate in sport,” said Vince Mayne, CEO at BUCS.

Clarity cannot come soon enough.

“The confusing information that clubs and students have received has had a profound impact on numerous teams and thus on their match results,” Porter said. “I know the Home Office is working hard to clarify the definitions, I just hope we can get our best team back on court before it’s too late.”