The SPFL transfer window has officially opened and Scottish clubs can now start chopping and changing their squads as they gear up for the new season.

Here, Press Association Sport takes a look at how effective the 12 Scottish Premiership teams were with their business during last summer's transfer window.

Aberdeen

Young midfielder Lewis Ferguson proved to be the pick of an otherwise unremarkable bunch, arriving from Hamilton on a compensation fee. However, a number of signings from England's lower leagues failed to establish themselves in the side.

Celtic

There may have been few signings at Celtic Park but record £9million buy Odsonne Edouard – signed permanently from Paris St Germain after a decent spell on loan the year before – and goalkeeper Scott Bain became vital players in team that went on to complete an unprecedented triple treble, although the returning Emilio Izaguirre had a disappointing second spell at the club.

Dundee

Nathan Ralph arrived on a free from Woking and looked the bright spot in a disastrous season for the Dens outfit. Signings like Jean Mendy and Benjamin Kallman did not provide the much-needed goals as the Dens Park side were relegated.

Hamilton

Accies made 12 additions in total as former boss Martin Canning looked to reshuffle his squad. Aaron McGowan and the returning Ziggy Gordon both became mainstays in the full-back slots. New boys Scott Martin and Tom Taiwo helped beef up the midfield numbers as Hamilton eventually scrambled to safety under Brian Rice.

Hearts

Target-man Uche Ikpeazu looked a handful early on, until a broken foot sidelined him just as Craig Levein's side were starting to purr. Irish defender Jimmy Dunne also impressed on loan from Burnley but saw his spell end in January before joining Sunderland.

Hibernian

Stevie Mallan was Hibs' top scorer with 13 goals after arriving from Barnsley, and Daryl Horgan also impressed after joining from Preston North End. Ghanaian winger Thomas Agyepong showed promise but found himself injured more often than not.

Kilmarnock

Goalkeeper Daniel Bachmann came in from Watford on loan and helped form a tight Killie defence, but Mikael Ndjoli found himself on the periphery mostly as Steve Clarke largely opted to stick with the tried-and-trusted squad that had served him so well the season before.

Livingston

Kenny Miller joined as a player-manager but it was the briefest of stints before Livi called time on the experiment. Liam Kelly was brought in from Rangers and proved to be one of the signings of the season, keeping 14 clean-sheets in the process and ensuring the top-flight new boys' comfortable survival.

Motherwell

Striker Danny Johnson came from English non-league outfit Gateshead and became a reliable impact player, while new goalkeeper Mark Gillespie established himself as first-choice with regular stopper Trevor Carson sidelined for much of the season after a bout of deep vein thrombosis.

Rangers

Steven Gerrard's first act after taking over at Ibrox was to build his side a solid backbone, with Allan McGregor and Conor Goldson added to the defence, while free-signing Scott Arfield provided goals from midfield. Liverpool winger Ryan Kent came in on loan and was named the SPFL Young Player of the Season.

St Johnstone

Drey Wright looked a shrewd signing and source of creativity, until a serious knee injury ended his campaign in early November. Former Celtic striker Tony Watt signed from FC Leuven but – despite a bright start – failed to live up to his early promise.

St Mirren

New Buddies boss Alan Stubbs's decision to replace the core of Jack Ross' Championship winning side nearly ended in disaster. It cost Stubbs his job just four league games into the season as replacements like Cole Kpekawa, Hayden Coulson and £70,000 buy Josh Heaton proved not fit for purpose, while only Paul McGinn and Lee Hodson played regularly throughout the season.