PAUL LAMBERT, the former Celtic midfielder, believes Rangers' failure to win promotion will be detrimental to Scottish football and warned it was not a certainty that the Ibrox side would go up next year either.

Motherwell's aggregate 6-1 play-off victory ensured they retain their place in the SPFL Premiership at the expense of Rangers who must now prepare for a fourth consecutive season outside of the top division.

Lambert, who spent eight years as a player at Celtic Park, felt the absence again of the Old Firm derby from the fixture list would be bad for the city but agreed that Motherwell, another of his former clubs, deserved to stay in the top flight. Rangers will rebuild again in the summer for another season in the Championship alongside Hibernian, St Mirren et al and Lambert warned there were no guarantees they would definitely win promotion at the second attempt either.

"It's maybe not good for Glasgow or Scotland because the city needs a strong Rangers as well, they are pivotal to," said the former Aston Villa manager as he lent his support to the Tesco Bank Football Challenge event at Hampden. "Celtic need that. If I was a Celtic player you would want your strongest rivals to be in the league because you need that. When we played it was great games in the Old Firm games, top players on both sides. As a player you would want your biggest rivals to be in the same league as you.

"It could take [Rangers] longer than another season [to win promotion], but they have to earn the right to be there. Whether that takes spending money to rebuild the team, the support is there and always will be for them.

"Sometimes you have to take a step back to go forward. I think that everybody thought they'd automatically go bounce, bounce, bounce through the divisions. But Motherwell were in the Premiership anyway and they were used to playing at a higher level of football. Rangers weren't and in those two games Motherwell earned the right to stay in the league. They were the better team over those two legs."

Lambert admitted he could understand why Rangers have struggled given all their off-field problems. He added: "It's hard to say [it's been a missed opportunity] because there has been so much disarray. So many things have happened, people blaming each other and the authorities getting involved. There have been so many problems and they've had to try to keep a handle on the playing side. They had to get a team that would win on the pitch and if they were winning - going from league to league to league - that would have masked a lot of things. But because they've hit a wall at the minute and they are not coming up, the question is being asked: "where do they go?"."

Lambert conceded that Rangers' demise has at least brought about a genuine spread of the major domestic trophies. Since the Ibrox club went into administration in February 2012, seven different clubs have won either the League Cup or Scottish Cup.

"That is good. I totally agree with that but that can happen even if Rangers and Celtic are in the same league. It can happen, it happened in my time, St Mirren beating Dundee United in 1987. All you need is five games to win the cup. Celtic and Rangers can draw each other. So it can happen whether Celtic and Rangers are in the top league or not."