Defender becomes Jackett's first Pompey signing
Pompey have signed defender Nathan Thompson on a two-year deal.
The 26-year-old will officially become a Blues player on July 1 when his contract with Swindon expires.
Assistant manager Joe Gallen said: “It’s nice to get the first signing over the line and we’ve brought in a very talented and experienced League One performer.
“We’ve got every confidence in Nathan that he’s going to do extremely well for Pompey.
“He’s a good ball player and is an excellent talker and motivator – and he can play in a number of positions.”
"We’ve brought in a very talented and experienced League One performer."
Thompson progressed through the ranks at the County Ground and made 187 appearances for the Robins.
He was awarded his first professional contract in 2009, while his senior debut arrived in a victory over Torquay the following year.
Thompson helped Swindon secure the League Two title in 2012 and skippered them to the League One play-off final in 2015.
He can play at right-back or in the centre of defence, while he is also comfortable in a midfield role.