LONDON -- The top four European leagues are set to automatically qualify four teams each to the group stage of the Champions League from 2018-19, according to multiple sources.

UEFA's executive committee is expected to approve the measure when it meets later this month, sources said, part of a set of changes to the European competition that will be implemented for the cycle between 2018-2021.

The club competition committee, led by Fernando Gomes of the Portuguese Football Federation, had been involved in tough negotiations for some six months with stakeholders, including a number of clubs from top leagues who threatened to boycott the Champions League if their demands were not met.

The additional guaranteed slots will be agreed as a compromise after UEFA was able to stand firm in denying many of those demands, as well as staving away the threat of a breakaway European Super League at least through 2021.

According to sources, the demands had included entry to European competition based on "historic merit" -- a "parachute" for popular clubs who fail to qualify on the pitch -- as well as the possibility of European ties to be played at weekends so as to increase broadcast audiences, and the creation of a new entity -- co-owned by UEFA and the clubs themselves -- to run the Champions League.

Changes to the Champions League would put five more teams from top leagues directly into the group stage. PIERRE-PHILIPPE MARCOU/AFP/Getty Images

Based on the current UEFA country coefficient ranking, the four countries who would benefit directly from the measures are Spain, Germany, England and Italy.

Currently, the top three leagues qualify three teams directly to the group stage, with a fourth having to endure a two-legged playoff round. The fourth-ranked league enters two teams directly to the group stage, with a third into the playoff round.

The change would give the top four leagues five more guaranteed teams, for a full 50 percent of the 32 group-stage slots.

Leagues from other countries, including France in fifth and Russia in sixth, can move into the top four coefficients based on their clubs' performances in European competition.