Newcastle owner Mike Ashley has been warned he risks creating a lost generation of supporters if he fails to invest in the club. Thousands of fans stayed away from Sunday's Barclays Premier League defeat by Tottenham at St James' Park in protest at the way the sportswear Tycoon is running the club, with the official attendance of 47,427 - the capacity of the stadium is in excess of 52,000 - understood to include many season ticket holders who did not attend. Protesters are calling for a repeat when Swansea head for Tyneside on Saturday, but Mark Jensen, editor of online fanzine www.themag.co.uk, fears longer-term consequences. Newcastle owner Mike Ashley has been urged to invest in the club or risk losing a generation of fans . Newcastle fans hold up 'Ashley Out' banners, mocked in the style of his Sports Direct chain of stores . Thousands of Newcastle fans boycotted the club's last game, a 3-1 defeat at home to Spurs on Sunday . Jensen, who himself stayed away from Sunday's game, said: 'I feel sorry for young people, what they are watching now and this lack of ambition. At least when I was young, the team might have been rubbish and we were going nowhere, but it was exciting to be on the terraces. 'There was so much more wrapped up in it, whereas now if the football is rubbish, I'm not quite sure what the lure is. 'That's a long-term danger. Whether Mike Ashley is here in the future or not, there's a danger that you are turning all these people off Newcastle United and going to the match, especially with the rival attraction of being able to watch it in your local pub.' Unofficial estimates have put the actual attendance for the 3-1 defeat by Spurs at significantly lower than 47,000, although some have seemed wildly optimistic. However, there is little doubt that those who answered calls for a boycott made an impact. Jensen said: 'I thought it was a massive success. Comparing it with the walk-out at the end of last season, basically it's always going to be symbolic. 'It's not going to bring Mike Ashley to his knees, but to have thousands and thousands of people, or whatever figure you want to put on it, who have already paid for something not going to the match... 'Imagine thousands of people going to Tesco or Sainsbury's and buying £30 worth of shopping and saying, 'Hang on a second, I'm not happy, you can have your shopping back'. It's a massive statement.' Last week's revelation that the club banked in excess of £34million as well as recording a profit of £18.7million for the last financial year has simply served to increase anger among fans, who have seen a squad assembled on a budget struggle to compete during the second half of the current campaign, and not for the first time in recent years. Tottenham striker Harry Kane nets his 20th league goal of the season to round off a 3-1 win over Newcastle . A fan holds up a sign protesting against Ashley's ownership as Newcastle slump to a sixth straight defeat . Newcastle midfielder Remy Cabella (left) jostles for possession with Tottenham's Paulinho (right) on Sunday . They have not been placated by head coach John Carver's insistence that there will be investment during the summer, and an increasingly vocal lobby are demanding that Ashley sells up. Jensen said: 'When you see the benefits that he's getting, as well as now profits in each of the last four years and the way that the TV income is going, to those people who say, 'Why isn't there a buyer? There isn't one' - why wouldn't there be a buyer? 'The climate of Premier League football has totally changed due to these TV deals, and so if you have got a sustainable Premier League club, especially one with the third biggest attendances, at the right price - and with a willing seller - there is definitely a buyer out there.' In the meantime, Carver faces the task of attempting to end a run of six successive league defeats, which has left the club just seven points clear of the drop zone, against the Swans. He said: 'I think there's enough experience to deal with it, yes. But we have got to stop losing players, though, sendings-off, injury...' Newcastle fans point towards the club's rude financial health amid poor performances on the pitch .
Newcastle owner Mike Ashley is an unpopular figure at the club for his perceived lack of ambition and investment in the last few years .
Mark Jensen, editor of the Newcastle fanzine, The Mag, predicts that unless Ashley changes his approach the club will lose supporters .
The Magpies have lost their last six consecutive league games .
Thousands of supporters boycotted the last defeat by Spurs on Sunday .