Reform Scotland said only an outright ban on short sentences could bring about change in the justice system.
Memorial For Fallen Police Officers
The bravery shown by police officers such as Keith Palmer in the Westminster terror attack will be remembered at a new police memorial.
A campaign is being launched on Wednesday to raise funds for the project, which is to be built at the National Memorial Arboretum (NMA) in Staffordshire.
While £2.5 million has already been raised, £4 million is needed for the UK Police Memorial, which will bear the names of more than 1,400 police officers and staff who have died while carrying out their duties.
Home Secretary Amber Rudd said: "Every day, our police officers and staff go out to work not knowing what they might face, but do so with the utmost professionalism and bravery.
"We all owe them a huge debt of gratitude.
"That bravery was plain for everyone to see in the phenomenal response of the police to the shocking events in Westminster back in March, as a result of which Pc Keith Palmer tragically lost his life.
"It is entirely fitting that those officers and staff who give their lives in the line of duty should be remembered with a lasting tribute.
"The Government has already committed £1 million towards the UK Police Memorial and I hope the public also take this campaign to their hearts and recognise the importance of establishing a permanent place of remembrance.''
It is eight weeks since the police constable was killed alongside four members of the public in the Westminster terror attack in March.
Sir Hugh Orde, chairman of the UK Police Memorial Trust, said: "Pc Palmer's death has put greater emphasis on the need to create a place where the nation can honour and commemorate our police service and where family, friends and colleagues of those killed on duty can go to carry out personal acts of remembrance.
"The NMA is the place where the nation can go to remember our services and the men and women who have been killed in the course of their duty for their country.
"We need to establish a fitting memorial that recognises the vital contribution that policing makes to our society and acknowledges the courage and sacrifice made by police officers and police staff who have paid the ultimate price.
"That tribute must become part of the fabric of our national life.''
The memorial will also feature an interactive space, telling the stories of those who have sacrificed their lives and is expected to be completed by 2019.
Further information about the memorial, including how to make a donation or take part in fundraising activity can be found at the UK Police Memorial website www.ukpolicememorial.org.
Anyone making a donation of more than £20 will receive a black and white Sillitoe Tartan wristband inscribed with the words "courage and sacrifice''.
The SNP leader admitted the word "national" could be "hugely problematic".
A police watchdog probe was launched after the remains of the 52-year-old were found in a house in Dumfries in February last year.
The accident happened at about 7.50pm on Thursday in Moodiesburn, North Lanarkshire.
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