Schröder
© delfi.eeGerhard Schröder:
German lobbyist and former politician, who was the chancellor of Germany from 1998 to 2005 and former leader of the Social Democratic Party of Germany (SPD)
In a recent interview with Berliner Zeitung, Gerhard Schröder claims that in March of 2022, "the Ukrainians did not agree to peace because they were not allowed to". According to the former German Chancellor, "they first had to ask the Americans about everything they discussed" and "nothing could happen because everything else was decided in Washington".

Schröder is now the fifth person to state that the West opposed a peace deal in March/April of 2022. In April of 2022, the Turkish Foreign Minister Mevlut Cavusoglu told the broadcaster CNN Türk:
Following the NATO foreign ministers' meeting, it was the impression that ... there are those within the NATO member states that want the war to continue, let the war continue and Russia gets weaker. They don't care much about the situation in Ukraine.
Then in May of 2022, one of Zelensky's "close associates" told the newspaper Ukrainska Pravda that Boris Johnson was an "obstacle" to negotiations because he'd brought two simple messages:
Putin is a war criminal, he should be suppressed, not negotiated with. And secondly, if you are ready to sign any agreements on guarantees with him, then we are not. We can with you, but not with him, he will still abandon everyone.
Then in September of 2022, Putin himself claimed:
"A peaceful settlement obviously did not suit the West, which is why, after certain compromises were coordinated, Kiev was actually ordered to wreck all these agreements."
Then in February of this year, the former Israeli Prime Minister Naftali Bennet (who served as meditator between the two sides) said in an interview:
"There was a legitimate decision by the West to keep striking Putin, to take the 'more aggressive approach'. And as a consequence, they broke off negotiations."
We also know that the two sides were in fact close to reaching an agreement. As Fiona Hill and Angela Stent wrote in Foreign Policy last September:
According to multiple former senior U.S. officials we spoke with, in April 2022, Russian and Ukrainian negotiators appeared to have tentatively agreed on the outlines of a negotiated interim settlement:
Russia would withdraw to its position on February 23, when it controlled part of the Donbas region and all of Crimea, and in exchange, Ukraine would promise not to seek NATO membership and instead receive security guarantees from a number of countries.
Returning to the recent interview with Schröder, he claims that he "received a request from Ukraine as to whether I could mediate between Russia and Ukraine". Specifically, he was asked to "convey a message to Putin". Indeed, Schröder is known to be a friend of the Russian President (which in the absence of other evidence would cast doubt on the veracity of his claims). He then liaised with Rustem Umierov, who has a close relationship with Zelensky.

There were five points the deal needed to address, he says:
First: Ukraine's renunciation of NATO membership. Ukraine cannot meet the conditions anyway.
Second: the problem of language. The Ukrainian parliament has abolished bilingualism. That has to be changed. Third: Donbass remains part of Ukraine. But Donbass needs greater autonomy. A working model would be that of South Tyrol.
Fourth: Ukraine also needs security guarantees. The United Nations Security Council plus Germany should provide these guarantees.
Fifth: Crimea. How long has Crimea been Russian? For Russia, Crimea is more than just a region, but part of its history.
The fact that no agreement could be reached was "fatal" in Schröder's view "because the result will now be that Russia will be tied more closely to China, which the West should not want."

He refrains from speculating as to why the Ukrainians were "not allowed" to cut a deal.

The existing evidence points to two reasons:
First, Western leaders were concerned that Putin would renege on the agreement - that he would "abandon everyone", in the words of Boris Johnson.

Second, Western leaders felt that with Russia's invasion floundering, there was a chance to "weaken", "press" or "smash" Putin.
Whether these are good reasons can certainly be debated. What's harder to dispute is that the West did oppose a peace deal - one that might have ended the conflict last spring, saving countless lives.