Ben Alnwick broke into the Sunderland first team in the 2004-05 season and made 22 appearances for the North-East club before being signed by Spurs on 2nd January 2006 for a fee of £900,000, which could have risen to £1.3 million depending on the conditions attached to the deal.
As a youngster, Alnwick was capped by England at Under-17, Under-18 and Under-19 levels, before he broke into the squad for the England Under-21s for their UEFA European Championship qualifier against Moldova.
Involved in a newspaper scandal before he left Sunderland when he was shown in a sex video with a 16 year old girl on the Internet.
Signed as one for the future, Ben failed to displace neither Paul Robinson nor Radek Cerny in the first team in his first season at the club, so moved to Luton Town, but was recalled on 24th October 2007 because of an injury to Paul Rbinson. He did go out on loan again, this time to Leicester City in January 2008, but he returned to Tottenham for pre-season training ahead of the 2008-09 season. However, with the signing of the experienced Cesar Sanchez, Alnwick was consigned to the reserves until he joined Carlisle United on loan for a month in October 2008.
When Ben returned to Spurs, he found a new manager in charge and he got his chance under Harry Redknapp when Gomes was injured and he was thrust into the League Cup semi-final second leg at Turf Moor, where he made a couple of mistakes, but Spurs managed to go through on aggregate after extra time. He featured in the next match - a Fourth Round FA Cup tie at Old Trafford - and made one more appearance at the end of the 2009-10 season at Burnley in a 2-3 defeat after Spurs had already secured fourth place in the table. In between he had gone on loan to Norwich City, only to pick up a hip injury and return early, then in October 2010, he went to Leeds United on a month's loan.
In the spring of 2011, he joined Doncaster Rovers on loan as cover for the injured Neil Sullivan, but failed to make an appearance, with a further loan at Leyton Orient in the latter part of the 2011, making a few appearances in an impressive stint at Brisbane Road, where he had replaced injured Spurs team-mate David Button, who had been the previous loan keeper.
On 1st June 2012, Ben was released from his contract by Tottenham and signed a deal with Championship side Barnsley, getting sent off on his debut with the Tykes. September 2013 saw him released from his contract with the Yorkshire side and two days later he signed for Charlton Athletic as a free agent. In January 2014, Alnwick returned to Leyton Orient for an undisclosed fee transfer, but an injury reduced his time there. After two months at Brisbane Road, Ben left for personal reasons, with his contract being cancelled on 24th March and during the summer of 2014 had trials with Bradford City and Blackpool. However, just when it looked like he was about to sign for the Tangerines, he was offered a three year deal with Peterborough United and signed with the London Road outfit.
Two years into his time at Peterborough, Alnwick asked to be released form his contract for personal reasons and on 31st August 2016, he was released from his deal with the club. The same day, he joined Bolton Wanderers and at the end of the season, his performances had won him the club's supporters' Player of the Year as the club gained promotion as runners-up in League 1. With the Trotters going into administration and with a huge debt causing problems in retaining staff and being deducted points, Alnwick failed to begin a game in the first half of the season and had his contract cancelled in December 2019 with immediate effect.